Outlook access via POP Access continuously fails

Outlook access via POP Access continuously fails with Message:

ERROR (0x800CCC92) while performing Task; "*** myname@zoho.com - Check for new Messages"
Answer from Servers: -ERR Access Restricted. Please try again using pop.zoho.com "

I've no Issue to login via Web Access but since this morning POP Access doesn't seem to work for some reason.
Tried already to setup the Acc from scratch in Outlook, but no change. Still can't use POP Access. It always asks me for Login and Password. No Issues with any other Accounts in my Outlook...