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Connection Issues FAQ

Troubleshooting guide for ERP connection problems.

Connection Test Failures

Section titled “Connection Test Failures”

Q: Connection test fails with “Connection refused”

Section titled “Q: Connection test fails with “Connection refused””

A: The ERP server is not accepting connections.

Check:

  1. ERP server is running
  2. Correct hostname/IP address
  3. Correct port number
  4. Firewall allows outbound connection

Q: Connection test times out

Section titled “Q: Connection test times out”

A: Network path to ERP is blocked or slow.

Try:

  1. Ping the ERP server from TaprNext host
  2. Check firewall rules
  3. Verify VPN connection (if required)
  4. Increase timeout setting

Q: Connection works sometimes, fails other times

Section titled “Q: Connection works sometimes, fails other times”

A: Intermittent network or load issues.

Check:

  1. Network stability
  2. ERP server load/availability
  3. Rate limiting on ERP API
  4. Token expiration timing

Authentication Errors

Section titled “Authentication Errors”

Q: Getting 401 Unauthorized errors

Section titled “Q: Getting 401 Unauthorized errors”

A: Credentials are invalid or expired.

For API key auth:

  1. Verify API key is correct
  2. Check key hasn’t been revoked
  3. Generate new key if needed

For OAuth:

  1. Re-authorize the connection
  2. Check token hasn’t expired
  3. Verify OAuth app is still authorized

Q: Getting 403 Forbidden errors

Section titled “Q: Getting 403 Forbidden errors”

A: User lacks permissions.

Check in ERP:

  1. User has API access
  2. User can create/post invoices
  3. Required scopes are granted

For D365:

  • Verify app registration has correct API permissions
  • Check security roles assigned

For SAP:

  • Verify communication user authorization
  • Check business partner permissions

Q: Credentials work in ERP but not in TaprNext

Section titled “Q: Credentials work in ERP but not in TaprNext”

A: Different authentication method or missing configuration.

Verify:

  1. Using correct auth type (API key vs OAuth)
  2. All required fields are filled
  3. No extra spaces in credentials
  4. Correct API endpoint URL

SSL/TLS Problems

Section titled “SSL/TLS Problems”

Q: “SSL certificate verification failed”

Section titled “Q: “SSL certificate verification failed””

A: Certificate issue on ERP server.

Check:

  1. Certificate is not expired
  2. Certificate matches hostname
  3. Certificate chain is complete

For self-signed certs:

  1. Export the certificate
  2. Add to TaprNext trusted certificates
  3. Or disable verification (not recommended for production)

Q: “TLS handshake failed”

Section titled “Q: “TLS handshake failed””

A: TLS version mismatch.

Check:

  1. ERP supports TLS 1.2 or higher
  2. No cipher suite conflicts
  3. Network device not intercepting

Firewall and Network Issues

Section titled “Firewall and Network Issues”

Q: Can connect from browser but not from TaprNext

Section titled “Q: Can connect from browser but not from TaprNext”

A: Server-side firewall or network configuration.

Check:

  1. TaprNext server IP is whitelisted
  2. Outbound ports are open (443, 8080, etc.)
  3. No proxy blocking connection
  4. VPN requirements met

Q: Connection works locally but not in production

Section titled “Q: Connection works locally but not in production”

A: Different network configuration.

Compare:

  1. DNS resolution
  2. Firewall rules
  3. Proxy settings
  4. VPN/tunnel requirements

Credential Rotation

Section titled “Credential Rotation”

Q: How often should I rotate API keys?

Section titled “Q: How often should I rotate API keys?”

A: Follow your security policy, typically:

  • Every 90 days for production
  • Immediately if compromised
  • After personnel changes

Q: How to rotate without downtime?

Section titled “Q: How to rotate without downtime?”

A:

  1. Generate new credentials in ERP
  2. Update TaprNext settings
  3. Test connection
  4. Revoke old credentials

Q: OAuth token keeps expiring

Section titled “Q: OAuth token keeps expiring”

A: Refresh token may be invalid.

Try:

  1. Disconnect and reconnect OAuth
  2. Re-authorize with fresh consent
  3. Check OAuth app configuration

Testing Connections

Section titled “Testing Connections”

Quick Test Checklist

Section titled “Quick Test Checklist”
  1. Basic connectivity — Can you reach the ERP URL in a browser?
  2. Authentication — Do credentials work directly against ERP API?
  3. Permissions — Can the user create invoices in ERP directly?
  4. Network path — Are there firewalls, proxies, or VPNs in the way?

Connection Test in TaprNext

Section titled “Connection Test in TaprNext”
  1. Navigate to Tapr Settings > ERP Connection
  2. Click Test Connection
  3. Review results:
    • ✓ Connected successfully
    • ✗ Error message with details
Section titled “Related”