Christian Flem

@imorrish Your reply, while useful, does not answer the question. Has there still not been a concrete announcement regarding RER ?

This will work in a user context. When you add the event receiver to eg. a list using access tokens from an Azure app it will not fire, until you've...

@waaromikniet I've also noticed this. I believe the New-MgSitePermission/Grant-PnPAzureADAppSitePermission creates an ACS user for your SharePoint app. The error message in the header is because this is not an ACS...

@waaromikniet I've heard back from Microsoft Support. RER events are getting retired. See response below: Hello xxxx, Hope you are doing well. Thank you for your response. we have checked...

The context depends upon how the code that listens to the RER performs the auth. If using ACS, and an app then the rer will contain a context token, else...

You cannot directly verify the user, since you're not getting the ContextToken. What you can do is check who modified he item in SharePoint, to get who triggered the call....