Getting Authentication Failure

I am having trouble accessing all my emails for the past one week, I contact my domain host and check my server and everything seem to be working fine from their end. I submitted a support ticket to zoho about three days ago, I was asked to email a screen-shot of my issues and all my email account, which I already did and I am yet to get a response or any helping in fixing the issue. Also anytime I try to enable any of my email account, it automatically goes back to disable. I need help please I am really stuck.

Thanks