"Windows Live Domain Services returned an access error Unable to connect to the remote server"
Hello Ray Yang,
Thank you for your response. Actually my problem is caused by migration exceptions, since the mailboxes are new users (empty) they do not actually need to be migrated, the AD users are synced correctly, so I we could just assign a mailbox to the new users (skipping migration for specific users) we would not have to resolve the migration issues.
My problem in detail is already described in topic: community.office365.com/.../334016.aspx however I did not succeed in finding the solution. Online Connectivity tests show everything is fine.