Broadback wrote:
This morning when attempting to send messages from any email (I have a
number) to any address I get this error:

An error occurred while sending mail: The mail server sent an incorrect
greeting: Your IP address is on the XBL blacklist! Sending denied.
For further information and delisting procedure,
please see http://www.spamhaus.org/query/bl?ip=80.229.179.189.

The messages into the sent box, but is not received.
Any ideas please? I am running under windows 10, both have been stable
for some time.

It's saying that your mail server is on a blacklist that the recipient
organisation has subscribed to. I assume you don't run your own SMTP
server at home (because if you did, this error message would mean more
to you than it appears to), so it probably means your ISP is actually
blacklisted, which is unusual.

Is that IP address 80.229.179.189 your domestic IP address? It sort of
looks like one, so maybe you are somehow sending email out directly by
SMTP from your home network? If so, you'll have to use your ISPs SMTP
servers as a smart host.