Verify operation keep failing

For last 4 weeks, verify operation is keep failing. Backup seems to be working fine and I can restore data also. However, verify is keep failing on same server and then it skips verification of the remaining servers.

Initially, I get V-79-57344-33991 error (A backup storage read/write error has occured). Then, I get "Final error: 0xe00084c7".

I have already cleaned tape drives couple times and I am using new tapes. I would think that if there is a problem with dirty tape or drive then backup would fail. Here it is the verification which is keep failing.

Any help is appreciated,