Hello dear community,
unfortunately I have the problem that spreadsheets (.ods .xlsx) and digrams (.odg) can not be protected with a password.
After setting the password/pressing ok, the error message “(Username) disconnected” appears.
I have the same error also with Collabora Built-in Server. However, there the error message is slightly different.
Interestingly, setting the password, changing the password and opening the file works for text documents (.odt).
Anybody have an idea? 
Nextcloud 27.0.1
Nextcloudoffice 8.1.0
Collabora Office 23.05.1.2 (running via docker same server)
Apache/2.4.52
PHP 8.1.2-1ubuntu2.13