Please help us help you and fill where relevant:
Your LimeSurvey version: 6.5.1 (docker-image martialblog/limesurvey:6.5.1-240320-fpm-alpine)
Own server or LimeSurvey hosting: self-hosted
Survey theme/template: custom theme

I have the same or a similar issue as in this related post. As suggested there, I opened a new topic.
Our setup is LimeSurvey running in a docker container with AuthLDAP Plugin Version 1.0.0 activated.
It is configured to work with our AD.

Some but not all new users get the error message:

Then I create the user manually, set authentication to AuthLDAP and it works for them.
For some users the auto create user does work as expected.

Recently the message changed to (translated to English, so it could deviate a little)

Recently I activated the AuditLog plugin to help debugging this issue, so maybe this added the new lines?

Any help to debug and fix this problem would be appreciated.

 

User need a valid email address, your LDAP return a valid email address for all user ?

If not :

1. Return the issue community.limesurvey.org/bug-tracker/ (i really think we must remove mandatory email address for user)
2. Create your own LDAP Auth plugin assign a false email address to user

Thanks for the advice. I checked the AD and it seems, I have used the wrong attribute in the AuthLDAP config.
We have multiple attributes for the mail address, but the one I used did not have always a valid address.
I changed it to use an other attribute and now it works as expected.