Symfony Exception

Symfony Docs

Custom\Exception\UnexpectedServiceException

HTTP 503 Service Unavailable

It appears that no web server is responding on this subdomain.
This does not seem to be the expected web port — the service responding here cannot be identified from this request.

Custom\Exception\ UnexpectedServiceException

An HTTP request was made to this subdomain, but the response does not match any valid HTTP/HTTPS web server. It appears that a different service or a non-HTTP protocol is responding instead. 


1# Diagnostic (simplified):
2$ curl -I https://your-subdomain.tld
3curl: (52) Empty reply from server

5# A typical HTTP response would look like:
6# HTTP/1.1 200 OK
7# Server: nginx

9# Actual result:
10# no or invalid HTTP headers
11# → indicates a non-HTTP service responding.