How to fix a long deletion of a snapshot in Veeam during a backup (the progress bar hangs at 99% for several hours)?

Question

System administration

Good afternoon. So, the situation is:
There is a virtual host that has a virtual machine on which DFS is located. Backup is performed without shutting down virtual machines, via snapshot. The backup itself takes place in the normal mode, then the snapshot deletion begins. And here a problem arises: the removal process "hangs" for several hours at 95-99%. It may take an hour, or it may take 40 hours to delete. At the same time, working with files on DFS becomes very slow. Backups go to external storage. Enough space.
How can this be fixed?