Login not working when embedded

Hey there.

I managed to install and set up the OSP on a fresh server. everything is working fine when accessing the server via its own url.

however, I have to embed the channel into another website. I embedded not only the video, i embedded the whole site. Video is working, chat is working. But when I try to log in, enter my email address and password, click on login nothing happens. no error, no loading, just as I would not press the button.

Can anyone help me sort this out?

I have set the server as described in the standard install steps for single server, set my certbot for ssl and have a valid certificate. there is no other reverse proxy in front of the osp server.

EDIT: I tried first with opera gx which is not working. I tried then with firefox on my mobile which IS working. FIrefox on Desktop is working as well. Google Chrome is not working on my Desktop.

thanks in advance!