Changed channels and notifications Project email address - emails bounce after approval by email

[Vera Valshonok]

For the new project I have set a new email address: One for Notifications and one for in Channels.  All is set for the customers to be able to approve tickets by Email (through notifications), depending on their comment by email the ticket should Transition to a different status.

After setting new email addresses, when approving, right after the approval email is sent by the customer, they receive Bounce email.

What can be the reason for emails to bounce and how can I fix the process so that email addresses would work for us. Thanks

[Vera Valshonok]

In the email I see the message: 

CAUTION: This email originated outside of NeoGames. Do not click links or open attachments unless you recognize the sender and know the content is safe.