PROBLEMS WITH ICLOUD EMAIL IN APPLE MAIL

In the last months I get a permanent error in Apple Mail app with the iCloud account. An alert triangle appear on the the top of accounts window and if I click on the icon I receive this message:

"La connessione all'host “p37-imap.mail.me.com” sulle porte di default non è riuscita"

Nothing seems to work, while I can continue to read my emails on the other Apple device such iPad Pro and also from a Huawei phone. Anybody have a solution?

Thanks,

Claudio