I was able to create an account using my own domain. Issue is solved for me.
I have my own domain and using this domain I'm able to create an account for Jira (this ticket system) but not for the Minecraft website.
When trying to buy the Java edition of Minecraft via https://my.minecraft.net/nl-nl/store/minecraft/#register, I constantly get the error " IllegalArgumentException: Registration failed."
This means I'm not able to buy the game. Opening a ticket at Minecraft wil not work either because I don't have an account.
Can you tell me how can I buy the game?
FYI: I'm also not using any kind of VPN and I can share my domain name in a personal message.
As commented in WEB-1647: I was able to create an account using my own domain. Issue is solved for me.