No smtp, no imap, can't authenticate

No smtp, no imap, can't authenticate

Hey,

All my clients stopped getting e-mails and refuse to send e-mails because an invalid e-mail adres.
I'm very sure it's all correct and I can login perfectly fine in the zoho webmail, or the app.

This worked perfectly untill this morning 05:23 where according my mailapp the error occurred. We are 8 hours further now and I still can't use imap or smtp.
Any news on this? I am a business client and I need mail.