Backup Completed , however error?

Good day All,

Recently , I backup some data about exchange ," \Microsfot Information Store\Second Storage Group "

In job history, the  Status - it show Completed, however also have error message :

e00002fe - Cannot log on to MAPI with the specified credentials. Review the resource credentials for the job, and then run the job again.

and I tested, it cannot restore this file.

How can I fix this problem? on the other schedule, it can backup success & also can restore the job.

What's the problem?

 

FYR

Set type               : Backup

Set status             : Completed

Set description        : SAN Backup
Resource name          :\Microsoft Information Store\Second Storage Group

Logon account          : 
Encryption used        : None
Error                  : e00002fe - Cannot log on to MAPI with the specified credentials. 
			 Review the resource credentials for the job, and then run the job again.
Agent used             : Yes

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