I installed open project and I can hit it running on my server at ip:

15.75.0.91

Works fine, login and all.

I then setup my dns to handle that ip address as:

https://projects.mysite.com

(on site, this goes through a web server proxy apache based on another machine, offsite it goes through a different webfirewall setup as an apache server and redirects both to SSL) .  When I login through the DNS name, it hangs on the logging in and openproject logs state:

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.594551 #16339]  INFO -- : Started GET "/login" for 10.75.1.219 at 2023-03-14 13:28:53 -0600

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.596307 #16339]  INFO -- : Processing by AccountController#login as HTML

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.612367 #16339]  INFO -- :   Rendered account/login.html.erb within layouts/no_menu (Duration: 9.6ms | Allocations: 5247)

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.630528 #16339]  INFO -- :   Rendered layouts/base.html.erb (Duration: 17.8ms | Allocations: 10429)

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.630853 #16339]  INFO -- :   Rendered layout layouts/no_menu.html.erb (Duration: 28.1ms | Allocations: 15759)

Mar 14 13:28:53 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:53.631175 #16339]  INFO -- : Completed 200 OK in 35ms (Views: 26.2ms | ActiveRecord: 3.2ms | Allocations: 17953)

Mar 14 13:28:54 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:54.120094 #16339]  INFO -- : Started GET "/api/v3/configuration" for 10.75.1.219 at 2023-03-14 13:28:54 -0600

Mar 14 13:28:54 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:54.130324 #16339]  INFO -- : duration=9.06 db=1.13 view=7.93 status=200 method=GET path=/api/v3/configuration params={} host=projects.apo.nmsu.edu user=4

Mar 14 13:28:58 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:58.409988 #16339]  INFO -- : Started POST "/login" for 10.75.1.219 at 2023-03-14 13:28:58 -0600

Mar 14 13:28:58 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:58.413254 #16339]  INFO -- : Processing by AccountController#login as HTML

Mar 14 13:28:58 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:58.413405 #16339]  INFO -- :   Parameters: {"utf8"=>"✓", "authenticity_token"=>"UjOO2nb2ESHaKBuyR_EFp2VQilPZsYYkDqPWL4geCroieSK8ucbyX4sUXM7NnDNahgIWSqbbiBnxHFxcgUgtCQ", "username"=>"admin", "password"=>"[FILTERED]", "login"=>"Sign in"}

Mar 14 13:28:58 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:58.650658 #16339]  INFO -- : Redirected to http://projects.mysite.com/two_factor_authentication/request

Mar 14 13:28:58 projects openproject-web-1.service[16339]: I, [2023-03-14T13:28:58.650993 #16339]  INFO -- : Completed 302 Found in 237ms (ActiveRecord: 2.1ms | Allocations: 4183)

Not sure why the logging in hangs, maybe something with my proxies I setup (I did 0 setup for https or anything on the openproject side) I just set up wiki.js the sameway and that worked great.  I can post my local and outside apache configs for the sites in question if need be.  The redirected to two_factor_authentication/request is interesting to me as I never set that up.  Not sure if this normal behavior though.  Here for completeness is my local apache proxy settings anyway:

<VirtualHost *:80>
    ServerName projects.mysite.com
    ServerAlias projects
    Redirect "/" "https://projects.mysite.com/"
</VirtualHost>

<VirtualHost 15.75.0.152:443>
    ServerName projects.mysite.com
    ServerAlias projects
<If "%{HTTP_HOST} != 'projects.mysite.com'">
    Redirect "/" "https://projects.mysite.com/"
</If>

    SSLOptions +StdEnvVars
#Include extra/ssl-certs
Include extra/wildcardapo-ssl-certs
    ProxyPreserveHost On
    ProxyRequests Off
    ProxyPass       /   http://15.75.0.91/
    ProxyPassReverse    /   http://15.75.0.91/
</VirtualHost>

I haven't tested this from offsite but our web-firewall has a similar virtualhost setup from the DMZ.