My personal Openproject 11 docker instance ran for months without problems. Since yesterday every login is rejected. The log message is

WARN -- : Failed login for '<username>' from 127.0.0.1 at 2022-10-28 15:42:50 UTC: invalid credentials

The "password forgotten" dialog is not usable since email does not work. The log message is

[2022-10-29T11:05:50.867188 #72] ERROR -- : [ActiveJob] [MailerJob] [c045dbbd-4d65-4745-9e2a-850bbb418708] Error performing MailerJob (Job ID: c045dbbd-4d65-4745-9e2a-850bbb418708) from DelayedJob(mailers) in 6320.7
8ms: Net::SMTPSyntaxError (503 AUTH command used when not advertised):
/usr/local/lib/ruby/2.7.0/net/smtp.rb:981:in `check_auth_continue'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:743:in `block in auth_login'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:954:in `critical'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:742:in `auth_login'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:728:in `authenticate'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:565:in `do_start'
/usr/local/lib/ruby/2.7.0/net/smtp.rb:518:in `start'

The DB settings table shows correct values. What is the reason of  503 AUTH?

I tried to modify the password directly using hints from https://community.openproject.org/topics/1043, but no success.

How could it be that all passwords are invalidated suddently??

I am helpless and need good ideas...

Thanks, Frank