What server version do you have installed and which specific phone app (and version)?
Does the remote access status indicator stay green or is it just temporarily showing a green icon?
Have you (miss)configured a firewall on your server?
These are some of the things I would check. Keep in mind: sometimes the remote access checkbox could be red even if you can correctly access your server.
Hope this helps!
Moderator Edit: Moved from a duplicate post. @FordGuy61
I was able to get remote access to work but it turns itself off at least once a day and I have to manually go back in and click on it to make it work again.
Do you have a static IP address (IP reservation) for your server?
This should be configured in your router – if there’s no reservation, your router will dynamically re-assign a different IP. This could interrupt the remote access until Plex catches up.
Not sure if this is the same problem, but my Remote Access broke after the last major Server Update. I have been searching online for fixes, but no one seems to be talking about the same issue.
Everything in the server settings is green and good to go, but since the last major update, my phone and tablet apps will not connect remotely anymore. I am open to ideas or if someone knows of another thread that covers this issue. TIA