SBS 2011 Queue viewer operation failed with an exception

Hi

I run a server for a local business - they gave reported tonight that they can not send emails. It has been working fine for a while now.

I can RDP and open up Exchange console etc - I cant open the Queue viewer, it opens and keeps trying to load, it then brings up a error -

The Queue Viewer operation on computer "server.domain.local" has failed with an exception. The error message is: The remote procedure call was cancelle, It was running the command 'get-queue -ResultSize '1000' - returnPageInfo $true -sortOrder '+NextHopDomain' -SearchForward $true - BookmarkObject $null - BookmarkIndex '-1' - includeBookmark $false -server 'Server.domain.local"

*Swapped the actual domain and server name as above.

I really need help as I have so many people demanding it be fixed.

Thanks

James