Snapshot Pro seems to freeze site, no backups created.

I've used snapshot pro to migrate some sites into our new multisite, and it has worked flawlessly. Today, I came back and network activated it and set up dropbox destination. I set up scheduled backups, as my intention is to use it for daily backups of the entire multisite.

I have made a few attempts at running a backup, and each time the entire site starts running so slowly it's unusable. The backup also never complete. The backup folder has not been created in Dropbox, even though authentication completed without any issues.

So far, the first scheduled backup has not been attempted. I just set it up this morning and have been trying to perform the first backup manually.

The site is new and only has a few sites on it. There are a couple clients running a fairly large media library, but surely snapshot can handle a bunch of pictures, no?

The site is well supported resource-wise, and the vps has never flinched on me before. I've enabled support access in case it helps. Any insight is much appreciated. As it stands, snapshot pro has been a lifesaver when it comes to backing up and migrating individual sites, but when it comes to backing up our multisite as a whole, I can't seem to get it to do anything other than crash.