Snapshot fails unless we snapshot through vSphere first
We have some severs that we snapshot once a week. They fail when the job runs. If I re-run the job on our off night, it still fails (this tells me this isn't any sort of load problem). If I take a snapshot via vSphere client, and remove it, and then run the job, it works. One thing that stands out to me is after the manual snapshot, the next snapshot (done by backup exec) is much quicker. This is probably because the data is already quiesced. Is there a snapshot timeout that we're hitting when the job normally runs?
Try setting the registry keys from this technote to see if that resolves the issue. This will allow BE to retry taking the snapshot a few times before failing.
https://www.veritas.com/support/en_US/article.100028133
Note the reg key in step for might be HKEY_LOCAL_MACHINE\SOFTWARE\Symantec intead of Veritas, depending on when and what version of BE you have installed.