e00084f8 - The network connection to the Backup Exec Remote Agent has been lost

I have thisproblem  for couple of monthes ... after 2 or 3 succefull backup there come 1  failed backup with this error

Set type               : Backup
Set status             : Completed
Set description        : Backup Template 0001

Resource name          : \\********\E:
Logon account          : *********\administrator
Encryption used        : None

Error                  : e00084f8 - The network connection to the Backup Exec Remote Agent has been lost. Check for network errors.

Agent used                     : Yes
Advanced Open File Option used : Microsoft Volume Shadow Copy Service (VSS)

Infact the E: drive is on the backup server itself , so i don't understand why it needes network connection

When I check service all backup exec service are running and port 10000 is opened also ...

do anybody have any idea ..about this