Troubleshooting

Precium S2S Troubleshooting Guide

This guide helps you diagnose and resolve common issues when integrating with the Precium S2S API.

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Diagnostic Decision Tree

Use this flowchart to identify your issue category:

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flowchart TD
    A[Issue Encountered] --> B{Error in Response?}
    B -->|Yes| C{HTTP Status?}
    B -->|No| D{Unexpected Behavior?}
    C -->|4xx| E[Client Error]
    C -->|5xx| F[Server Error]
    E --> G{Status Code}
    G -->|400| H[Bad Request - Check payload]
    G -->|401| I[Auth Error - Check API key]
    G -->|403| J[Forbidden - Check permissions]
    G -->|404| K[Not Found - Check endpoint/ID]
    G -->|422| L[Validation - Check data format]
    F --> M{Is it intermittent?}
    M -->|Yes| N[Retry with backoff]
    M -->|No| O[Contact support]
    D -->|3DS not completing| P[3DS Issues]
    D -->|Webhooks not arriving| Q[Webhook Issues]
    D -->|Charges failing| R[Payment Issues]

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Authentication Issues

Issue: "401 Unauthorized" Response

Symptoms:

JSON

{
  "error": "Invalid or missing API key"
}

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Solutions:

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Verification:

BASH

curl -X GET https://gate.reviopay.com/api/v1/clients/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Accept: application/json"

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Issue: "403 Forbidden" Response

Common Causes:

• S2S not enabled for your account
• Attempting operations outside your permission scope
• IP restrictions in place

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Solution: Contact Precium support to verify your account permissions.

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Request Validation Issues

Issue: "400 Bad Request" or "422 Unprocessable Entity"

Check these common mistakes:

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Missing Required Fields

JSON

// Wrong
{
  "currency": "ZAR",
  "products": [{"name": "Test", "price": 100}]
}

// Correct
{
  "client_id": "uuid-here",
  "brand_id": "your-brand-id",
  "currency": "ZAR",
  "products": [{"name": "Test", "price": 100}],
  "success_redirect": "https://example.com/success",
  "failure_redirect": "https://example.com/failure"
}

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Wrong Amount Format

JAVASCRIPT

// Wrong - decimal amount
{ "price": 299.00 }

// Correct - cents as integer
{ "price": 29900 }

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Invalid Expiry Format

Wrong: 12/2028, 2028-12, 1228
Correct: 12/28 (MM/YY format)

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Invalid Currency

Wrong: "Rand", "rand", "R"
Correct: "ZAR" (ISO 4217)

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3DS Issues

Issue: 3DS Challenge Not Loading

flowchart TD
    A[3DS Not Loading] --> B{Form submitted correctly?}
    B -->|No| C[Fix form submission]
    B -->|Yes| D{Correct fields included?}
    D -->|No| E[Add MD, PaReq, TermUrl]
    D -->|Yes| F{Correct target URL?}
    F -->|No| G[Use 3ds.3ds_url]
    F -->|Yes| H[Check browser console for errors]

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Required 3DS Form Fields:

HTML

<form method='POST' action='{{3ds_url}}'>
  <input type='hidden' name='MD' value='{{MD}}' />
  <input type='hidden' name='PaReq' value='{{PaReq}}' />
  <input type='hidden' name='TermUrl' value='{{callback_url}}' />
</form>

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Issue: 3DS Callback Not Received

Causes:

• callback_url not accessible from internet
• Firewall blocking incoming requests
• URL mismatch (http vs https)

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Solution: Ensure your callback URL is publicly accessible, uses HTTPS in production, and returns HTTP 200 within 5 seconds.

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Issue: 3ds_authentication_failed Error

Allow the customer to retry. If persistent with a specific card/bank, investigate with Precium support.

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Direct Post Issues

Issue: "Direct Post URL Expired"

Cause: Direct post URLs are single-use and expire after the first submission.

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Solution: Create a new purchase to get a fresh direct_post_url.

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Issue: Card Data Submission Fails

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Working Example:

BASH

curl -X POST "DIRECT_POST_URL" \
  -H "Authorization: Bearer YOUR_S2S_API_KEY" \
  -H "Content-Type: application/x-www-form-urlencoded" \
  -d "cardholder_name=John Smith" \
  -d "card_number=4000000000001091" \
  -d "expires=12/28" \
  -d "cvc=123" \
  -d "remote_ip=196.21.45.123" \
  -d "user_agent=Mozilla/5.0" \
  -d "accept_header=text/html" \
  -d "language=en" \
  -d "java_enabled=false" \
  -d "javascript_enabled=true" \
  -d "color_depth=24" \
  -d "utc_offset=-120" \
  -d "screen_width=1920" \
  -d "screen_height=1080"

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Charge/Payment Issues

Issue: Charge Returns Error

flowchart TD
    A[Charge Failed] --> B{Check error code}
    B --> C{Type?}
    C -->|Validation| D[Fix input data]
    C -->|Auth Failure| E[3DS not completed]
    C -->|Decline| F{Soft or Hard?}
    C -->|Network| G[Retry later]
    F -->|Soft| H[Can retry with same card]
    F -->|Hard| I[Request different card]
    E --> J[Complete 3DS first]
    D --> K[Correct and retry]

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Pre-Authorization Issues

Issue: Capture Fails After Authorization

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Diagnostic Steps:

1. Check purchase status — must be "authorized"
2. Verify capture amount ≤ authorized amount
3. Check authorization age (7-30 days typical expiry)

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PYTHON

purchase = client.get_purchase(purchase_id)
if purchase['status'] != 'authorized':
    print(f"Cannot capture - status is: {purchase['status']}")

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Issue: Partial Capture Not Working

Error:partial_capture_not_supported

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Solution:

• Capture the full amount and refund the difference, OR
• Void and create a new authorization for the correct amount
• Contact Precium to enable partial capture

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Issue: Pre-Authorization Void Fails

PYTHON

purchase = client.get_purchase(purchase_id)
if purchase['status'] == 'paid':
    # Already captured - use refund
    client.refund_purchase(purchase_id)
elif purchase['status'] == 'authorized':
    # Can void
    client.void_purchase(purchase_id)

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Zero Authorization Issues

Issue: Zero Auth Not Permitted

Error:zero_auth_not_permitted

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Solutions:

1. Contact Precium to enable zero authorization
2. Use a minimum amount (e.g., R1.00) and immediately refund
3. Use network token validation instead

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Issue: Zero Auth Doesn't Generate Token

PYTHON

purchase = client.create_zero_auth_purchase(
    client_id=customer_id,
    currency='ZAR',
    success_redirect='https://...',
    failure_redirect='https://...',
    force_recurring=True  # Required for tokenization
)

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External 3DS (MPI) Issues

Issue: External 3DS Data Rejected

Error:invalid_external_3ds_data

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PYTHON

# Wrong - missing is_external_3DS
payment_details = {
    "card": {
        "cavv": "AAA...",
        "eci_raw": "05"
    }
}

# Correct
payment_details = {
    "card": {
        "is_external_3DS": True,  # Required
        "authentication_transaction_id": "YOUR_MPI_TX_ID",
        "cavv": "AAA...",
        "eci_raw": "05",
        "ds_trans_id": "uuid-here"  # For 3DS2
    }
}

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Issue: External 3DS Brand Not Configured

Error:external_3ds_not_enabled

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Cause: Must use a Non-3DS brand for external MPI. Contact Precium to create a Non-3DS brand.

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Network Token Issues

Issue: Invalid Network Token

Error:invalid_network_token

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Request fresh token from MDES/VTS and verify token requestor ID is correct.

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Issue: Cryptogram Expired

Error:cryptogram_expired

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PYTHON

# Request fresh cryptogram immediately before transaction
cryptogram = request_new_cryptogram_from_token_service()
# Submit transaction immediately after

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Webhook Issues

Issue: Webhooks Not Arriving

flowchart TD
    A[Webhooks Not Arriving] --> B{URL configured in dashboard?}
    B -->|No| C[Configure webhook URL]
    B -->|Yes| D{Endpoint accessible?}
    D -->|No| E[Check firewall/DNS]
    D -->|Yes| F{SSL valid?}
    F -->|No| G[Fix SSL certificate]
    F -->|Yes| H{Returning 200?}
    H -->|No| I[Fix endpoint code]
    H -->|Yes| J[Check Precium webhook logs]

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Verification:

BASH

curl -X POST https://your-webhook-url.com/precium \
  -H "Content-Type: application/json" \
  -d '{"test": true}'

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Issue: Webhook Signature Verification Fails

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Debugging:

PYTHON

print(f"Received signature: {signature}")
print(f"Timestamp: {timestamp}")
print(f"Raw payload length: {len(payload)}")

message = f"{timestamp}.{payload.decode('utf-8')}"
computed = hmac.new(secret.encode(), message.encode(), hashlib.sha256).hexdigest()
print(f"Computed signature: {computed}")
print(f"Match: {hmac.compare_digest(signature, computed)}")

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Issue: Webhook Timeout Errors

Solution — Async Processing:

PYTHON

# Wrong - synchronous processing
@app.route('/webhook', methods=['POST'])
def webhook():
    data = request.json
    process_payment(data)  # Slow - might timeout
    return '', 200

# Correct - acknowledge immediately, process async
@app.route('/webhook', methods=['POST'])
def webhook():
    if not verify_signature(request):
        return '', 401
    webhook_id = request.headers.get('X-Webhook-ID')
    queue.enqueue(process_webhook, request.json, webhook_id)
    return '', 200  # Return immediately

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Issue: Duplicate Webhooks

PYTHON

import redis
redis_client = redis.Redis()

def handle_webhook(data, webhook_id):
    cache_key = f"webhook:{webhook_id}"
    if redis_client.exists(cache_key):
        return  # Already processed
    redis_client.setex(cache_key, 86400, "processing")
    try:
        process_event(data)
        redis_client.setex(cache_key, 86400, "completed")
    except Exception as e:
        redis_client.delete(cache_key)
        raise

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Issue: Testing Webhooks Locally

BASH

# Install and start ngrok
ngrok http 3000
# Use the generated URL in Precium dashboard
# e.g., https://abc123.ngrok.io/webhooks/precium

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Trigger a test webhook:

BASH

curl -X POST https://gate.reviopay.com/api/v1/webhooks/test/ \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "event": "purchase.paid",
    "webhook_url": "https://abc123.ngrok.io/webhooks/precium"
  }'

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Payment Decline Issues

Issue: "insufficient_funds"

• Notify the customer of insufficient funds
• Suggest retry after funding the account
• Offer alternative payment methods
• For MIT: Schedule retry per retry logic

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Customer Message:"Your payment couldn't be processed due to insufficient funds. Please add funds to your account and try again."

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Issue: "do_not_honour"

Potential Causes:

• Card restrictions
• Unusual spending pattern
• Bank's fraud detection
• Account issues

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Actions:

1. Suggest the customer contact their bank
2. Offer an alternative payment method
3. For MIT: Retry per schedule

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Issue: Token-Based Charge Fails

Common Causes:

• Token expired
• Original card expired/replaced
• Wrong previous_network_transaction_id
• Incorrect original_amount_cents

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Verification Checklist:

• Token is from the same client
• previous_network_transaction_id matches original CIT
• original_amount_cents matches tokenization amount
• is_recurring: true in purchase

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Issue: Refund Amount Exceeds Original

PYTHON

original_amount = 29900
already_refunded = 5000
max_refundable = original_amount - already_refunded

if requested_refund > max_refundable:
    raise ValueError(f"Can only refund up to {max_refundable}")

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Issue: Refund Pending for Days

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Testing Issues

Issue: Test Cards Not Working in Production

Test card numbers only work in the sandbox environment. Use real cards in production.

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Issue: Real Cards Not Working in Sandbox

Sandbox doesn't process real cards. Use designated test card numbers for sandbox testing.

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Performance Issues

Issue: API Requests Are Slow

Optimisation Checklist:

1. Use connection pooling
2. Implement request timeouts
3. Cache client IDs (don't create new clients each time)
4. Use webhooks instead of polling for status

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PYTHON

import requests
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

session = requests.Session()
retry = Retry(total=3, backoff_factor=0.5)
adapter = HTTPAdapter(max_retries=retry, pool_connections=10, pool_maxsize=10)
session.mount('https://', adapter)

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When to Contact Support

Contact Precium support (support@precium.com) when:

• URGENT priority errors persist
• Unexpected error codes not in documentation
• Settlement or reconciliation discrepancies
• Account configuration issues
• Suspected fraud or security concerns

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Include in Support Request:

• Purchase ID(s)
• Timestamp of issue
• Full error response
• Steps to reproduce
• Expected vs actual behaviour

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Error Code Quick Lookup