Troubleshooting search error 503
When you use the advanced search feature in HTML files exported from Dr.Explain, you may encounter error messages with code 503 instead of search results.
A 503 error means the server is temporarily unable to handle your request. This usually happens due to rate limiting or the server being overloaded.
Common causes
-
Rate limiting: too many requests in a short time has triggered web server's internal protection. Wait a moment and try again.
-
Server overload: the server is busy handling too many requests. Wait and try again later.
-
Backend failures: repeated backend errors caused the web server to stop sending requests. Check Troubleshooting error 502: bad gateway.
This step requires access to your server's log files.
For nginx:
sudo tail -f /var/log/nginx/error.log
Look for these messages:
-
"limiting requests" — rate limiting is blocking your requests. Go to Step 2.
-
"limiting connections" — too many connections from your IP. Go to Step 2.
-
"no live upstreams" — the backend has been marked as down due to repeated failures. Go to Troubleshooting error 502: bad gateway to check if the backend is working.
This step requires access to your server's configuration files.
Rate limiting might be configured in your nginx configuration:
limit_req_zone $binary_remote_addr zone=mylimit:10m rate=1r/s;
Or in Apache:
<IfModule mod_qos.c>
QS_SrvMaxConnPerIP 10
QS_SrvMaxReqPerIP 100
</IfModule>
If rate limiting is too strict: contact your server administrator to adjust the limits or whitelist your IP address.
This step requires access to your server via SSH and Docker.
Check if the server is overloaded:
docker compose stats
Look for: high CPU or memory usage on the backend or Solr containers.
If resources are maxed out: the server might be overloaded. Wait a few minutes and try again, or contact your server administrator to increase resources.