Google Home Assistant Action - Reviewer can't access

Question

We are trying to wrap up a Google Home/Assistant Action release for a "works with google" device set. We had add 2FA (Pin) per google requirements and this triggered a manual review. The google reviewer is reporting that when they select the action from the list they get a "Could not reach [test] Action Name". We have no problem adding this action through our various test accounts and phones on our end. Screenshot from Google reviewer below.

Reading through past threads on the internet, it sounds like it could be a problem with the particular Google reviewers phone/app version which is out of our control. However, in attempt to try every option available in our control, I am looking for other fixes to try?

Reviewer Screen Shot

One thread suggested that possibly the language settings for the action can impact a users ability to access the action. Initially, we had the app set to just English with no locales checked. We attempted to add English (US) to this. But I presume the tester based on the timing of testing is possibly in India. Has anyone run into lack of locales or language setting which could cause this error? Although I attempted to change my phone to English (Canada) which didn't cause the error the reviewer is reporting.

Second, we are authenticating with Azure B2C. Again, we used a VPN so traffic would come from a few different countries outside the US including India, and this did not limit B2C login availability. Although, it did post a user risk alert in the B2C dashboard.