iCloud Mail is currently not working in Australia (8am 31 Jan):
and the rest of the world:
Its now May and I am having more “issues” with iCloud Mail on a Mac. I have recently sent emails using my iCloud account to recipients who also have iCloud addresses. The emails go through the Outbox then Sent. They then show up as “sent” on all my devices. However they are not received by the addressees. I have checked their junk folder and there is no sign of my emails. They are vanishing into the ether!
The problem seems to be with Mac Sonoma (latest version) as iOS emails seem to get through.
Currently I am sending important emails via another account and/or using SMS to check that they have been received.