(I'm not sure if this is the correct forum because probably not a Spark/xtra problem - but not sure where to post it).

A friend in Australia uses Skymesh for his emails. I have been sending him emails for years but in recent days all my emails have bounced back with message “Mail Delivery System<postmaster@xtra.co.nz>  Mail Delivery Failure”.

The email address I’m sending to is correct and other people are not having any problem sending to him. I’m sending from iPad using xtra email on Apple mail app. Just tested sending from MacBook Pro and getting same result.

The error message I get is long and detailed and way beyond my comprehension. The first few lines of the message say: 

Quote:

This message was created automatically by the mail system (ecelerity).

A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed:

“friend@skymesh.com.au” (after RCPT TO): 554 5.7.1 Service unavailable; Client host [210.55.143.52] refused by SkyMesh; blocked by UCEProtect; IP 210.55.143.52 is UCEPROTECT-Level 1 listed. See http://www.uceprotect.net/rblcheck.php?ipr=210.55.143.52

Reporting-MTA: dns; xtra.co.nz

Arrival-Date: Fri, 20 Jan 2023 19:28:01 +0000

Unquote

Would be grateful for advice.