Incoming Email Disabled

Incoming Email Disabled

Hello!

Some email accounts have been disabled. But when I activate it, I can not enable inbound mail. I followed the guidelines of this link: https://www.zoho.com/mail/help/adminconsole/email-administration.html#alink4

However, when I click on incoming disabled I receive a message that can not be enabled.

Please, how can I solve it?