Edge Not Displaying Images With Palo Alto Networks Generated Page

[EichmannCharity]

Recently our Network guys implemented a Palo Alto firewall and we have started using it to block content. For instance a user tries to go to a gambling website and they get a blocked message that has a couple of images that are hosted on a different IIS based web server but the main page itself is hosted on the Palo Alto.

IE and Chrome display the website and the images fine. Edge displays the webpage OK, but the images are missing.

To troubleshoot, I have tried on my own domain joined machine (IE Good, Chrome Good, Edge no images)

I have tried on a non-domain machine that is using only our public wifi and not our internal network (IE Good, Chrome Good, Edge Good)

I have tried on a machine that had been joined to the domain but I removed it and left it on the internal network still (IE Good, Chrome Good, Edge Good)

Back on my domain joined machine where Edge does not display the images and I saved the webpage to that local machine and opened the saved html file (IE Good, Chrome Good, Edge Good)

I changed the HTML code in my locally saved version of the webpage to point to the remote images that Edge is not able to display when the page is presented from the Palo Alto and referencing the images (IE Good, Chrome Good, Edge Good)

I then went to an IIS server and created a new app and pointed to the local HTML page but still to the remote images (IE Good, Chrome Good, Edge Good)

Based on these tests, the only time Edge has a problem showing the images is on domain joined machines where the main webpage is hosted on the Palo Alto and the images hosted on a separate server but works fine under all other testing scenarios. Again, Chrome and IE work fine under all configurations including the 1 that does not work in Edge.

I also added the Palo Alto's IP to the trusted sites but still, no joy

As 1 final test I just built a brand new win 10 machine. Immediately after joining the domain and before logging on with a domain account for the first time, I moved the machine to an OU with absolutely no GPOs applied. I also moved my test user to the same OU with no GPOs. I logged on as my test user and the images were broken in Edge. So it is not a GPO setting or anything causing this behavior. It is strictly that any domain joined machine pulling the website from the Palo Alto, Edge is not displaying the images hosted on another server.

Anyone have any suggestions on what else I can check or has anyone else seen anything like this? We do have a support request open with Palo Alto as well.

[reaper]

have you set up a wireshark or tried the built-in sniffer (ctrl-shift-E) to see what edge does differently from other browsers?