Mailboximport request stuck at 0%

Hello,

i am doing a mailboximport-request which stops at 0% (this will also happen with other mailboxes).

My configuration is exchange 2010-environment with a dag (1 online, 1 offline).

All mailboxes are online at the moment..but the import will not start.

edit:

i ALSO tried the following :

Delete DAG + Members

Create NEW DAG --> Everything working fine

When adding a "database copy" on the 2nd server in the dag process wil start slower but will work.

When bringing down the 2nd server in the dag again same problem ---> Percent complete 0%

What is the problem here?