hello, I'm trying to install OCS3 with these guidelines
Everything went good. But I'm experiencing the following problem after configuring the front and backend adress. I get this: Network Error.

Front and backend are running on the same server. I changed the DNS entry's for the front and backend like in the doc.

Is there a way to check that the front-end has connection with the back-end? Logs in the backend are pretty empty. Nginx logs are not telling something. I
I already disabled UFW. I'm running this on a ubuntu 24.04.4 LTS
So I'm pretty stuck :-)
Do you need more info, I'll happy to give it :-)
Kind regards