Error message received when using club email address

Yesterday, I sent out messages to the members via the club member email address. I started getting bounce backs saying that a member's email was not valid. It is. No email addresses have been changed.
Then I received this message a minute ago:
Member Glenn Ross, ACS have bounced too many times and exceeded the FreeToastHost limit for bounces.

This automatically generated message is to notify you that this email address ***has been removed*** from the FreeToastHost database to prevent it from causing further bounces.

Repeatedly attempting to send emails to invalid, non-working email addresses hurts the overall email reputation of the FreeToastHost system and will not be tolerated.

Please ensure that valid, functioning email addresses are in use to prevent further actions of this nature in the future.

If you have any questions about this warning, please visit support.toastmastersclubs.org

Can someone provide some guidance? Thanks, Glenn Ross

We require the club number to provide any assistance.

6379 West Austin II Toastmasters in Austin, TX. Thanks.

What is Glenn's email address?

Recipient Email Address: txglennross@gmail.com
Email Subject: [FreeToastHost] Message Not Delivered: West Austin II Toastmasters
Date Sent: Tue, 15 Dec 2020 22:26:55 +0000

Diagnostic Code: 550-5.1.1 The email account that you tried to reach does not exist. Please try
Delivery Status: 5.1.1 userunknown
Date Last Attempted: Tue, 15 Dec 2020 22:26:55 GMT

Txglennross@gmail.com