IMAP not working

IMAP not working

I just signed up for Zoho CRM after checking in my trial account that email integration works with my IMAP mail account. I got it working successfully for myself and 2 colleagues. I then went ahead and paid for accounts for 5 people.

As soon as our accounts were converted to paid accounts, IMAP stopped working and is no longer available as an option - only POP3. Our mail service does not support POP3 so this is not an option. Our accounts are Professional. No response from support to my ticket, and no-one available by phone.