We have two SharePoint 2019 farms. One is in DomainA (dev farm) - the other in DomainB (productive farm).
We created a new Web Application on the farm within DomainA, gave permissions to users from that domain (e.g. DomainA\JSmith) and everything worked fine. Since this is the dev farm we moved the Web Application to DomainB to take the site live.
Up until now everything seemed to work fine with the site on DomainB until a new user from DomainA needed to work on it. In this case we usually create an AD group in DomainB and then add the users from DomainA to that group. After that we assign that group the appropriate permissions on the site(s) since there is no full trust between these domains.
However in this case it just does not work. Permissions only work for DomainA users who have already been added to the site before the move took place. New users from DomainA don't have any effective permissions when being added to that AD group. If I create a new user in DomainB that user instantly has the desired permissions on the site through that AD group.
So a workaround for the time being would be to give the new user an account within DomainB but this should (ofc) not be the final solution.
Any help/pointers are appreciated in getting the permissions to work again!