This message was deleted.

We have the same product and don't see that error. Just wondering if there is any BCR in place? We don't have BCR.

Nope BCR is disabled when you click the mark as phishing button does it open in a iframe/pop up window within Outlook?

I guess I was mistaken. I don't have a mark as phishing... I have Spam button from Proofpoint/MailShield add-in. Sorry to lead astray on that. Clicking the Spam button though appears to use Edge WebView, which doesn't really help either.

Might be same add in the add in is called Proofpoint phish alarm. When I click the get add in button in outlook I can see it's admin deployed so looks like it is pushed out and configured from the O365 admin center so guess they can choose what it is called. Locally when I test it on outlook it pops up in the iframe/pop up I do see mswebview2 running under the outlook exe process so guess it using mswebview2. I do have mswebview2 runtime installed on Citrix and latest version of MS edge so not sure why it's not working