Zoho email suddenly stopped working - any ideas to fix this ?

Zoho email suddenly stopped working - any ideas to fix this ?

Zoho  email suddenly stopped working.

although got this sent to me

Reporting-MTA: dns; mx.zohomail.eu
Arrival-Date: Wed, 26 Aug 2026 12:48:05 +0100

Original-Recipient: rfc822;
Final-Recipient: rfc822; 
Status: 421
Action: delayed
Last-Attempt-Date: 26 Aug 2026 12:33:51 GMT
Diagnostic-Code: Host not reachable.
Remote-MTA: dns; 76.223.67.189 

any help, greatly appreciated