Members and Subscribing still wont work even on Ghost v4 (401 Error)

I also just upgraded to v4 and can’t seem to get subscriptions to work despite mailgun saying I’m good to go.

An issue seems to be that gmail addresses aren’t recognized as valid
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Despite definitely being valid.

Oddly enough, my gsuite email does work (albiet by landing in my SPAM inbox)
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Here’s how things look in my admin tab:

I’m using Namecheap for the domain and am self hosting ghost. Why do regular gmail addresses not work here? It looks like this may be a recurring issue?