Troubleshooting

Common symptoms, their possible causes and the solution steps.

• Users see "503 Service Unavailable" / "No Available Server"; what should I do?LB-16-001
• The vService cannot be reached at all; what should I check step by step?LB-16-002
• It works when the backend is accessed directly but not through TR7; why?LB-16-003
• The change I made does not seem to take effect; what should I check?LB-16-004
• I get 502 Bad Gateway; what are the possible causes?LB-16-005
• I get 504 Gateway Timeout; which timeout should I check?LB-16-006
• A backend shows as down; how do I diagnose it?LB-16-007
• The site became slow behind TR7; where should I start?LB-16-008
• I get a certificate error; how do I diagnose it?LB-16-009
• Legitimate users are being blocked; how do I find which rule is blocking them?LB-16-010
• Traffic is not distributed evenly across the servers; how do I investigate?LB-16-011
• The Health Check is "up", but users get errors; why?LB-16-012
• An infinite redirect loop occurred; why?LB-16-013
• My application keeps sending users back to the login screen (the session is lost); why?LB-16-014
• Large file uploads fail; why?LB-16-015
• The backend application generates http:// in absolute URLs; how do I fix it?LB-16-016
• How do I follow a specific user's problem in live traffic?LB-16-017
• Which information should I collect before contacting TR7 support?LB-16-018
• Can I capture packets on TR7 and download them as a pcap (tcpdump)?LB-16-019
• How do I download the encrypted diagnostic bundle for the support team (Encrypted Support Bundle)?LB-16-020
• What does the configuration error(s) warning in the vService preview (DNS Resolution Error, Port binding error) mean; where does Port Collision appear?LB-16-021
• How do I test from TR7 whether a server's port is reachable?LB-16-022
• How do I check which IP address TR7 resolves a domain name to?LB-16-023
• Can I run a load test against a vService or a Backend Service from TR7?LB-16-024
• How do I test from TR7 which TLS versions and ciphers a server supports?LB-16-025