Building a new AD network I've setup a forest: alpha.forest and the tree root domain beta.local so all the users will log on to the domain 'beta'.
The automatic trust between them is only one way; if I validate the trust on Alpha it's fine. If I validate the trust on Beta if fails with access denied. I then log in with Alpha's admin credentials and I'm told it's all good. I then retry the test and if fails again.
Can't see any errors in either event log at all.
Any advice most welcome.