No Emails Flowing To Zoho TeamInbox

No Emails Flowing To Zoho TeamInbox

From today, any emails we send to our TeamInbox addresses fail to be delivered.

Our TeamInbox is connected via IMAP to 2 x Zoho Mail accounts. If I log in to those accounts directly via Zoho Mail, I can see all the emails landing in the inbox.

The emails are never delivered to TeamInbox. I checked IMAP settings and everything looks good. This has broken overnight with no settings being changed from our end.