Blizzard is looking into an issue for Steam players who have run into an error with today's patch: «Trial Version Ended» displays, even after having bought Diablo 4.
With today's launch of Diablo 4 Patch 1.5.2, Steam players previously able to play the game with no issues discovered an interesting «trial period» bug upon login. Even those who purchased the full version of Diablo 4 experienced this issue, and Blizzard has acknowledged that it seems to affect all Steam users:
Patch 1.5.2 Now Live
While there is currently no ETA for this fix, Blizzard usually has these types of bugs taken care of quickly — stay tuned for any updates to this situation!