Unable to send emails

[Matkim]

I can't send emails to any address via Outlook or Post Office.
In Post Office I get the following error;
Failure sending message: email address not valid. Please use an email address that looks like user@example.com

[BasilDV]

Hi @Matkim

Welcome to the Community!

May we know the error message you received when you send an email via Outlook client?

What troubleshooting have you tried so far?

Please send me a PM with your TPG username or customer ID number along with your email address.

BasilDV