"User could not be authenticated. This IP appears to be having trouble signing in to an account (detected repeated failures)"
This is what I get with a fresh install of Plex 1.2.4.2949-4e494e4.
The server is running Ubuntu server 16.10 with a fixed IP address.
I can browse to the web app using my external IP as well so NAT seems to be working on 32400 at least.
I just can't claim the server and it says it's not available from outside.
On the remote address tab I see this>
Not available outside your network
First sign in to access your server from anywhere.
Signing in results in the first message.
Please help.