Troubleshooting Server error responses
When encountering the following server error responses—Internal Server Error (500), Bad Gateway (502), Service Unavailable (503), and Gateway Timeout (504)—it typically indicates issues with the server hosting the URL.
Troubleshooting
- Review your server's access logs for the 30 minutes before and after the error occurred.
- Look at the response codes of other requests. If they’re also failing (e.g., 502, 503, 504), the server might be overloaded or under maintenance.
- Access the URL using a browser, cURL, or Wget from the machine running the applications manager.
- If the response code returned in browser is 500, 502, 503, 504, then check the URL's server for overload.
- If the response returned in browser is 200, suggesting the issue might be elsewhere.
- Proxy Server Configuration: If your environment requires the use of a proxy server to access the URL, configure the proxy in Applications Manager. Click here to learn how to configure the proxy.
- Bypass Proxy for the URL : If you have configured a proxy in Applications Manager but want to bypass it for the server host/IP, add the host/IP under the "Do not use proxy for addresses beginning with" section in the "Configure Proxy" page: Navigate to Settings > Product Settings > Proxy Server Settings.
500: Internal Server Error
A 500 error is a generic error indicating that the server encountered an unexpected condition that prevented it from fulfilling the request. It could be due to
- Server misconfiguration
- Unhandled server-side exception
- Code errors in web applications
- Resource overload (e.g., database or server failure), etc.
Solutions
- Check server logs for detailed error messages. Ensure that there are no issues in server-side scripts or applications.
- Admins can also check memory management for reallocation possibilities.
502: Bad Gateway
The server, while acting as a gateway or proxy, received an invalid response from an upstream server. It could be due to following reasons:
- Upstream server is down or unreachable or overloaded and cannot handle the request, leading to a timeout or malformed response.
- A reverse proxy (e.g., NGINX, HAProxy, or a load balancer) is not configured correctly and cannot communicate properly with the backend servers.
- The proxy server cannot resolve the upstream server's domain name due to DNS misconfigurations or DNS server outages.
Solutions
- If it doesn't fix itself with time, the user can clear their cache and cookies, hard reload the page, or try again in safe browser mode.
- Ensure that the upstream server is functioning correctly and reachable.
- Admins can check the name server, firewalls, and DNS settings.
- Admins can also check the error log for further clues. It could be a relay between other servers that suffers glitches in transit.
503: Service Unavailable
A 503 error occurs when the server cannot process the request temporarily. It could have several implications including
- Server maintenance running
- An overloaded server due to unexpected traffic surges or attacks, or even a client-side DNS configuration error.
- The server is rejecting requests due to too many incoming requests within a short time
Solutions
- If the server is under heavy load, consider implementing load balancing or autoscaling.
- Verify if there’s any rate limiting or throttling causing the server to reject requests.
- Ensure the server is not mistakenly configured for maintenance mode or temporary downtime.
- Monitor server resource usage (CPU, memory, etc.) to identify potential overloads.
504: Gateway Timeout
The server, while acting as a gateway or proxy, did not receive a timely response from the upstream server.
- Upstream server is down or unreachable or overloaded and cannot handle the request, leading to a timeout or malformed response.
- High network delays or poor connectivity between the proxy and upstream server.
Solutions
- Check the load on the upstream server to ensure it is not overwhelmed with requests.
- Check if the upstream server is responding within the timeout period.
In URL monitor, check "If monitor detects error, re-try immediately to verify error" option. This will allow Applications Manager to verify the server error before reporting the error thus avoiding false positives.
Still facing issues?
If the problem persists, contact our support team along with the following details:
- A screenshot of the "Add Monitor" page.
- The URL debug tool response for the URL monitor.
- Reproduce the issue and share the latest Support Information File (SIF) from Applications Manager, with the "Print all logs" option enabled. To do this, go to Settings > Logging, and choose "Print all logs".
New to ADSelfService Plus?
Related Articles
Troubleshooting Bad Request and Internal Server error
When a server responds with a Bad Request (400) or Internal Server Error (500), it typically indicates issues with how the request is being made or processed. The reasons for these errors can vary, but the most common causes are: Incorrectly ...Service is not running error troubleshooting
Follow the below steps to troubleshoot the error Check if the service instance is running in the host name specified. Check if the port number is given correctly. Retry with the "SSL is enabled" option both enabled and disabled in the add/edit ...Troubleshooting URL Monitor
Here are few of the common errors you may come across in URL monitor, we have mentioned the steps you can follow to troubleshoot them. General troubleshooting for URL monitor Ensure that the URL is accessible from the server in which Applications ...Mail Server Monitor - Troubleshooting
Common Mail Server Monitor Errors and Troubleshooting Guide 1. Unknown Host Error Description: This error occurs when the mail client cannot resolve the hostname of the mail server to an IP address. The issue typically arises from DNS resolution ...Real User Monitor (RUM) - Troubleshooting
If the monitor has not polled data for a long time, follow the steps below for troubleshooting: Step 1: Check the RUM Agent configuration Real User Monitor requires the RUM Agent to be installed and mapped to the Applications Manager. Refer the help ...