I am currently trying to package my first app and was able to install it. Now I have the problem, that I cannot open the app. When I am trying to open it, I just get redirected to the overwie off my apps (example.com//yunohost/sso/). When I am logged out, I get redirected to the login page, even if the App was installed as public app. The App is just using php7.2-fpm and nginx. I do not see any errors in the php7.2-fpm.log or in the example.com-error,log.
Since I do not get any error messsages, I do not have more information about this problem.
I would be happy, if anyone would be able to help me solve this problem.
You could try to test your app using the tool https://github.com/YunoHost/package_check to test your app. It will try to install/remove/upgrade/etc. You will not usually know why it fails but you will know if it runs from a technical point of point.
Also, you should start little and begin by serving a static page/file from nginx before wanting to add some php. You will be able to locale the error more easily I think.