When PowerApps binds an Image control to this URL, the request for the image is NOT authenticated. Only URLs that come from supported data types from within the SharePoint connector get rewritten so that PowerApps will be able to authenticate them safely. The Office365Users.UserPhoto() function retrive unautenticated image, so the PowerApps keep showing AuthenticationError.
There is a mitigation is to save profile image as an attachment to a employee item, and retrive image from the attachment. But for big company with 500+ employees, it’s hard to create a separate database for employee items with image as attachment. And it is double work, if the information is already existing somewhere, we should utilize the existing information.
PowerApps (or with help of Flow) somehow can retrieve the profile image by using office365users connector, and save it as an attachment to a list item when create the list item through a PowerApps app.
Please take consideration of this idea or give some other better solution to solve this issue in PowerApps. Thank you!