Desktop client does not connect

I installes yesterday nextcloud on my web server and everything went fine, no Problem to connect via web or android app.
Today I installes the web client, no problems, when i start it, i put in the URL, the user and password, then I give him the permission to connect and he starts to reconnet, but nothing else helps.
I tryed it with the app token, but it isn’t possilbe to sign in then.

I’m using win 10, the server is on a https subdmain,
php is version 7.2.11
the database is a Art: mysql Version: 5.7.20
nexcloud Version is:
and the desktop client Version is 2.5.0beta1 (build 20180803)

I found no help in the net and hope, somebody here has an idea.

Best greetings

Any errors in logs? Same result with stable 2.3.3 client?