Hi 
Can't look at logs to determine what's gone wrong, but I suspect that yes, you left the old VPS's client in a bad state and as a result there are a bunch of unfulfilled authorizations hanging around. You have three options:
- Wait. The pending authorizations will expire after 7 days. As long as your setup isn't continuously trying to create (and then never fulfill) new ones, the issue will go away soon. But if some system you can't stop is still creating but not fulfilling authorizations, then...
- Deactivate the authorizations. Unfortunately I don't think cPanel AutoSSL supports the ACME decativate-registration API, and getting your account key out of cPanel and into some other ACME client is probably hard-to-impossible. If you can do this, awesome, but more likely...
- Follow these instructions to "Recreate your registration". This will give your new VPS a new ACME account that doesn't have those 308 old pending authorizations still hanging around.
If the problem persists even after you create a new account, that means that something is messed up with your new VPS. It is creating orders for new certificates, but then not even attempting to fulfill the challenges to prove control over those domains. You'll need to figure out what's wrong with your setup or configuration to resolve the issue.