smtp; 554 5.7.1 [CS01] Message rejected due to local policy. Please visit https://support.apple.com/en-us/HT204137
Speaking on the message you get:
Then yes, you can continue to email them but using a different delivery server.Code:smtp; 554 5.7.1 [CS01] Message rejected due to local policy. Please visit https://support.apple.com/en-us/HT204137