The evening that 6.3 released on was I unable to login, because of the following issue:

Unable to complete version update. [30426][19900][2]

When I tried to use the "Restore Game Data" option in the launcher did another issue appear:

Unable to update patch files. [11006][20815][20866][19900][5]
D:/Steam/steamapps/common/FINAL FANTASY XIV Online/game/ffxiv_dx11.exe

I uninstalled and reinstalled the game once it appeared which solved the issue at first. But yesterday evening did it appear again and I don't want to wait 2,5 hours every few days to play the game.

Does anyone here know how to fix this issue? I'm not too experienced with things like this, so won't be able to understand all the terms when it comes to fixing it.