Alert Someone Notifications not Working


I am running into an issue where my 'alert someone' notifications are not sending.

I have a column that is formatted as a contact list, and my automation is set up to alert the email chosen in that contact list. However, the emails are not being sent. When I test it with myself, I DO receive the alert via email, when I test it with any other emails in the list, they do NOT receive the alert.

I have gone into personal settings and ticked ' Include my changes in sheet notifications' and I have gone into the cog in the automations window and ticked 'Unrestricted' .

Any advice would be much appreciated :)