Send an email V2: Delivery has failed to these recipients or groups in Power Automate workflow

Good afternoon,

I've created a workflow to send emails within our organization when an action has been completed. This works for 4 out of the 5 individuals in our org. However I receive the following Undeliverable message when sending to just one of our employees using the Send an email V2 in power automate.

I'm confused as why it sends fine to the other 4 individuals and just this one throws an error. 

Thoughts?

Delivery has failed to these recipients or groups:

Employee Name (mailto:employeename@company.com_
Your message wasn't delivered because the recipient's email provider rejected it.

Diagnostic information for administrators:

Generating server: CO1PR01MB7305.prod.exchangelabs.com

mailto:employeename@company.com_
Remote Server returned '550 5.7.520 Access denied, Your organization does not allow external forwarding. Please contact your administrator for further assistance. AS(7555)'