Click on Icon in Mailbox works, same URL in Browser not

First thanks for support yesterday.
Now nearly everything runs fine, but as topic says: I click on the icon in the mailbox list roundcube login screen come up. I copy the ling open a new browser window insert the link does not get a connection.

Rainer

 

I tried that on my server, it does work. Are you copying the link that ends with /webmail/