Syncing Unsubscribes with Mailerlite

Yesterday I connected the unsubscribe sync from the Automailer to Mailerlite (paid for).  Last night Mailerlite had to turn off the webhook that synced it as it was making too many calls (more than 500).

It did make the syncs and both Grow and Mailerlite updated.  

But I turned it on again (so it would not be doing “old” ones just new unsubscribes.  And Mailerlite had to turn it off again as it was making too many calls.

Has anyone got this working successfully?  Are there any further docs about this?