In very specific (and rare) circumstances, it will not be possible to AirPlay content using the Plex for iOS app. Specifically, this occurs if:
- You have set the Secure connections Plex Media Server preference to
Required(which is not the default value) and - Your network/router does not allow DNS Rebinding
When both of those two things are true, the AirPlayed content cannot connect to your server securely and thus the server will deny access.
How can I fix it?
There are a couple of ways you can fix things so that AirPlaying content will work.
Adjust Your Plex Media Server Setting
Perhaps the easiest is simply to change your Plex Media Server’s Secure connections setting back to the default of Preferred. That means that a secure connection will be used whenever possible, but in cases where it is not possible (like this particular situation), the server will allow a regular HTTP connection.
Related Page: Network
Make a DNS Rebinding Exception
In many cases, you can also adjust your router’s settings to make an exception for Plex regarding DNS Rebinding protection. The “How to Use Secure Server Connections” support article has information on that.
Related Page: How to Use Secure Server Connections