Backup Exec 2012 SP4 Credential Problem with ESXi 5.5 U1

Hı,

I have backup exec 2012 sp4 version. 

I upgraded my vcenter&esx to 5.5 u1 

I can backup physical servers.

I can add server from backup exec gui ( esx with root password , vcenter with domain admin password)

When I add esx server with root password its ok !

When I try to backup other virtual machines ,its failed with credential prompt.

When I check my credential to my esx server vcenter ok lots of server ok but last there virtual machines fail by credential.

Problem started with vcenter 5.1 upgrade to 5.5 u1 .

Is there any idea for fix this issue?

Thanks