Surely those of you who play Ni no Kuni on PC have experienced a server missing or the server you are playing on is not on the list, here I will provide a short tutorial to overcome this, go ahead!
Open Regedit
Open regedit by pressing windows key + R, then type regedit and press OK. 
Then navigate to the regedit that was opened earlier to HKEY_CURRENT_USER > Software > NetmarbleNeo > CrossWorlds.
Change Region
Once you’re done finding CrossWorlds the next thing is to change the region. Usually the region changes itself because we experience an abnormal disconnect, and causes the server to disappear. Click CrossWorlds in the folder and change the regional to the server you have created. 
Double-click the CONFIG_SAVED_JOINED_REGION_CODE section to change the value of that parameter.
- NAE = US
- EU = Europe
- ASE = Asia
Enter the code according to which server you live in, because I’m from Asia, so I enter ASE. 
Then click OK. Open the game as usual, surely the server you want has appeared again 😀 Those are the steps that need to be taken if the server disappears at this no kuni. Thanks for reading, hope this helps!
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