This is an issue with the primary launcher/patcher not being able to properly update the DOM for the UI.
If you want it to patch automatically, you don't really have a choice to keep trying it. If it doesnt work within 30 seconds, it won't magically start working so just close it and restart it.
Alternatively, you can manually patch your game and launch it with the alternative launcher (which has no patcher).
To do so, follow the manual patching tutorial here:
https://mabinogi.ir/thread/36-manual-patching-tutorial
Once you've manually patched the game to the latest version (which you can find here
http://mabinogi.ir/patch/p.txt, find the first number, ignore everything else), you will be able to use the Alternative launcher (version 1.1) to launch the game without patching it.