User cannot log-in using Firefox

Hi,

I have the following strange behaviour.

Nextcloud: 15.1.0 on an Raspi2 with external USB data drive

Windows 10 with Firefox (Quantum) 65.0 64-bit

When a user wants to login with the Firefox the log-in screen does not disapear and the user gets access to the data, instead the login remains and no error message occures.

Using instead of Firefox the Edge Browser, the login is working. Using a different windows 10 user, the login works with Firefox.

The nc-error.log and nc-access.log did not show anything that would show an hint, why the behaviour is so strange.

I have deleted the cookies for the IP Address and disabled the password storage for that IP-Addresse.

As the server is currently running in a private network without access to the internet (yet), I didnot activate Letscrypt and by that the certificate is not valid, but I have accepted the warning the first time I visited the server.

Do you have any idea?`

Thanks

Have a look at Have to login for 2-3 times until it works