Public URL Issue on MacOS computers

Hi,

I have a bit of a strange issue I’m struggling to get my head around.

I have a Raspberry Pi 3, which is running ScreenlyOS and has been solid for years. I still to this day on my various Windows computers, on various networks, access this via Public URL without issue.

However, I am trying to handover the task of uploading slides to Screenly to another individual, and this is where I’m facing issues.

The individual uses a MacBook as his daily computer, and he has tested the Public URL in various browsers (Including Chromium ones).

When attempting to access the public URL on his computer or phone, he is presented with a blank screen, and never sees the login prompt. To verify it was not a user error, I have even had a in person meeting with him, where I tested from his MacBook myself and experienced the same issue.

As mentioned, I can access the RPI via Public URL fine, on multiple Windows computers and my iPhone.

Does anyone have any idea what is going on or how to troubleshoot this further? The chair of this charity are now considering replacing the unit if I am unable to resolve this, and we would rather not incur any unnecessary costs.

Thanks.