A Hearthstone Hotfix is being applied this evening to the servers to fix issues with accessing the Arena and Transfer Student. This update will not require a patch.

Quote From cmdylux

Hey everyone,

We’re currently deploying a hotfix that will address the following items:

  • Fixed a bug preventing some player accounts from accessing Arena mode.
  • Fixed a bug where Transfer Student was not properly recognizing the game board when chosen as a Discover option.

This hotfix will take place on the server side, so you will not be required to download anything if you’ve already updated to 18.0.