I have a mailcow server at hetzner and when I attempt to send to iCloud I get this error:
to=<[email]@icloud.com>, relay=mx01.mail.icloud.com[icloud ip]:25, delay=7.8, delays=5/0.15/1.5/1.2, dsn=5.7.1, status=bounced (host mx01.mail.icloud.com[icloud ip] said: 554 5.7.1 [CS01] Message rejected due to local policy. Please visit https://support.apple.com/en-us/HT204137 (in reply to end of DATA command))
I have emailed iCloud about this but not yet received a response. Is there a way to resolve this issue?