Managed backups are not working on the site, snaphots do but randomly

I'm trying to create a managed backup of my multisite, but it is not working.

I'm getting this:

"REQUEST TIMEOUT
This request takes too long to process, it is timed out by the server. If it should not be timed out, please contact administrator of this web site to increase 'Connection Timeout'."

For snapshots, I was first getting this:

"An unknown response returned from Snapshot backup attempt. Aborting. Double check Snapsoht settings"

But after a few attempts, I was finally able to create a snapshot of the main site.