You are getting the following error while sending emails:
sorry, that domain isn’t in my list of allowed rcpthosts” it means that you need to enable SMTP or outgoing authentication in your email client.
This means you have not enabled authentication for outgoing messages in your email client. Open up your email client, go to Account Setup, find the outgoing mailserver configuration and make sure authentication is enabled for outgoing messagess. Your username and password is the same as your incoming mailserver. Some clients will ask what type of authentication, select Password.
E-mail is bouncing:
Please make sure the email is spelled correctly.
If the email you are sending to is "my name" <'firstname.lastname@example.org'> you must remove the ' (quotes) from inside the <>.
If you still need assistance, please contact support.