mod_matrix_gw fails to work on a multi-vhost setup

[poVoq]

Environment

• ejabberd version: 25.04
• OS: Linux (Fedora)
• Installed from: official rpm

Errors from log

[error] HTTP handler crashed: exception error: {module_not_loaded,mod_matrix_gw,<<"example.org">>}
in function  gen_mod:get_module_opts/2 (src/gen_mod.erl, line 430)
in call from gen_mod:get_module_opt/3 (src/gen_mod.erl, line 410)
in call from mod_matrix_gw:process/2 (src/mod_matrix_gw.erl, line 70)
in call from ejabberd_http:process/2 (src/ejabberd_http.erl, line 378)
in call from ejabberd_http:process_request/1 (src/ejabberd_http.erl, line 508)
in call from ejabberd_http:process_header/2 (src/ejabberd_http.erl, line 297)
in call from ejabberd_http:parse_headers/1 (src/ejabberd_http.erl, line 222)
in call from ejabberd_http:init/3 (src/ejabberd_http.erl, line 146)

Bug description

I run a ejabberd server with two vhosts, first example.org and second example.com. I configured mod_matrix_gw only for the second example.com via append_host_config:, but as seen in the error above it actually tries to redirect to the first example.org vhost when using the matrix federation tester (which triggers the above error message).

The Matrix federation tester itself returns: Connection Errors Non-200 response 502 from remote server.

I also noticed that when navigating to the mod_matrix_gw http endpoint via a browser like https://matrix.example.com:8448/_matrix I only get the ejabberd mod_http internal 404 error page and not a json response as I would expect if there was a Matrix s2s endpoint.

Thanks for the help.

[poVoq]

Might be related to this: #4102 (comment)

As this bug also effects my server and it presents the same wrong domain certificate to xmpp servers on s2s direct TLS connections.