If you've been having trouble connecting your Logic Remote app to Logic Pro X and you've been down all the other troubleshooting steps (checked firewall, checked for updates, etc) then I might have the solution for you.
Warning: techie steps ahead. Turn back now if you're not comfortable in the terminal.
First, open up your console. While looking at All Messages, search (upper right hand corner) for the word "logic" (no quotes). Look for a message that says something like this: