• pop.zoho.com
• imap.zoho.com
• smtp.zoho.com

The users accessing their accounts via POP or IMAP may get security alerts mentioning the certificate change. We suggest you to add the certificates to the trusted identities. 

If you are using the POP Server name as mailpop.zoho.com, please change the server name to pop.zoho.com in the mail client you are using. 

Please post here, in case you have any further questions.  

Regards,
Ramya A