YOURLS doesn't work anymore

Hello all,
I have a Raspberry Pi 4 and had yourls running before without any problems.
But since I set up the Nginx Proxy Manager I can’t get into the webinterface anymore. I get the error message: “502 Bad Gateway (openresty)”.
How can I get yourls running again?
Thanks for the help. Attached is a picture of the error message.

It’s an nginx configuration problem, not a YOURLS problem then.

No idea, not an nginx user myself.

Have you checked your nginx error log? Usually in /var/log/nginx/error.log unless you’ve configured otherwise.