I had issues with running Lbry while mining using Ethman remote monitor to see mining activity (claymores -mport -3333). The port for Ethman was using 3333 to locally access mining logs and Lbry needed that port to function. I switched mining monitor to port 3332 / -mport on the pc i was trying to open Lbry and it started up no problem. So if you're mining / using Ethman on port 3333 while trying to run Lbry it will give an error an exit.