"An error occurred during a connection to imap.zoho.com:993.
You have received an invalid certificate. Please contact the server administrator or email correspondent and give them the following information:
Your certificate contains the same serial number as another certificate issued by the certificate authority. Please get a new certificate containing a unique serial number.
(Error code: sec_error_reused_issuer_and_serial)"
A quick Google search shows this has happened before, but nothing recently. Hopefully it will be fixed soon!