Mail sent from a brandnew domain got rejected

[tino1974]

Hi

The last days I have built my veryfirst website. Unfortunately the mail I send to my employers mail-account get blocked...

"host mx1.hc1019-8.eu.iphmx.com [23.90.110.172]
    SMTP error from remote mail server after DATA:
    550 #5.7.1 Your access to submit messages to this e-mail system has been rejected."

What's the reason for? How can I solve this problem? 

Thx for help

Tino 

[Ken Stieers]

Wait 30 days, or get the recipient to put you in a exception list.
The Sender Domain Reputation feature (SDR) treats brand new domains as bad, as the VAST majority of newly created domains are automatically generated by bad actors.