Mail app is not showing whole messages

Hello,
I’m new to this forum. I signed up here because I have a problem with the mail app of Nextcloud. When I open a mail in the mail app it only shows me a portion of the message (see picture):

Has anyone an idea how to fix this? I’m running Nextcloud with the fpm-alpine image in a docker container.

The solution of the problem is the same as in this thread:
https://help.nextcloud.com/t/nextcloud-login-issue-google-chrome/65958