Stuck in "Trying to Enter Session"

@NukeSetra, There is a post with all the current known bugs:

I must note: this list of known bugs is not *official* as it is not posted by FiveM devs. 

Number 5, I believe is your issue. Please note that FiveM does not support any scripts/mods/resources so if you have any installed, please uninstall them and try again. Also, I know it’s already been said, but verifying your game normally helps this issue.

https://goo.gl/ssuZzh - Verify Social Club version of GTAV

If all else fails, I would try uninstalling both GTAV and FiveM (also check to make sure there are no folders leftover after uninstalling) then reinstall both again and hopefully that’ll fix your issue.