Login Button grayed

Hi community,

i have upgraded my owncloud system to nextcloud
Upgrade worked like a charme, no problems.
After changing the default theme to my own theme (which worked without any problems under owncloud) i have no chance to login any more: login button is grayed.
changing back to default theme: login button works.

Where can i find a solution for that?

Any help really appreciated.

Please have a look at Nextcloud Theming
Cheers, Carsten