Discord App Authorization Issues:

 

Error:
Please make sure FiveM is authorized in your Discord application and Discord desktop is running

Solution:
If FiveM is launched, close it and relaunch it, check your Discord window, and see if there is a pop-up for app authentication 
Ensure you’re not using Discord PTB; if you don’t know what PTB is, you more than likely don’t have it. Delete and Reinstall Discord.

If the basic fixes didn’t resolve the problem, try these advanced troubleshooting steps.

Clear FiveM and Discord Cache.
Steps to Clear FiveM Cache:
Close FiveM completely

Open the FiveM installation folder.
Go to FiveM Application Data > Cache and delete the contents inside.
Restart FiveM. Steps to Clear Discord Cache: Close Discord completely.
Press Windows + R and type %appdata%\Discord.
Delete the Cache, Code Cache, and GPUCache folders.
Restart Discord.

Check to see if you have FiveM in your Discord Authorized Apps:

If FiveM is not listed under Authorized Apps, then here are the steps to fix it; otherwise, your last resort is to reinstall FiveM and Discord:

On your keyboard, hit the Windows logo + R
Your "Run" Windows will pop >> type %appdata% and the enter Select CitizenFX >> Delete ros_id.dat

Close the window and go back to the Run window >> type: %localappdata% and delete "DigitalEntitlements"

Now, restart Discord by clicking on the app and use the keyboard shortcut "Windows key + R"
Relaunch FiveM to see if the authorization pops up