Hello,
I have a similar problem with email address @sfr.fr
SMTP error from remote server for TEXT command, host: smtp-in.sfr.fr (93.17.128.165) reason: 550 5.7.1 Email rejected per SPAM policy
This problem occurs with version 6.99 and 7.00 so I rolled back to version 6.98 and it works fine.
So please try to fix this problem in order to be able to run the last version.
Regards