Imap inbox suddenly empty for all mail clients ie ios, mac mail, outlook...

Imap inbox suddenly empty for all mail clients ie ios, mac mail, outlook...

Hi,

All the different mail clients we use all now show one of our imap zoho accounts inbox has having no emails.
If I log directly in to zoho there are 477 emails there in the inbox.
This is occurring on different PC and devices mail clients.

The sent and other folders for the account are showing the correct emails in all client, only the inbox is empty,
Our other zoho imap accounts are displaying correctly for all folders.

Why is the one accounts inbox no longer syncing for all mail clients?

Thanks
Dave