Error 2924 Unable to complete the request. Operation on the server xxx timed out.

Hi I use Microsoft Test Manager to deploy lab machines in an SCVMM environment. If I try to deploy VM templates everything works fine right away. When I deploy a VM based on a stored VM (not a VM template) I always get an error on the SCVMM server "Error 2924 Unable to complete the request. Operation on the server xxx timed out." When I click repair afterwards in Test Manager it tries to deploy the VM again and then the operation succeeds. Any ideas what causes this error each time?