Wekan knows only LDAP users that have logged in

I have activated Wekan for each user, but when I try to add a user to a board only those that have logged into the website in the past, are listed.
When I open the Administration→User page, I see only those users that have logged into the website in the past.
How can I add a user to a board, if that user has not used Wekan before?

Greetings
Daniel

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