Only stops working when on the Diablo 4 game - A button works on all other apps and games - A button on Xbox does not respond on the Diablo 4 Beta.
Often have to switch multiple controllers to get the game to work and use the A button - despite all controllers working fine on all other games and apps.
Same here. This is horrible. Makes the game almost unplayable! Hope they fix this soon
major bug game not registering button input - Console Bug Report - Diablo IV Forums (blizzard.com)
Need more attention on this issue
I just bought the game last night, 6/15/23, and the game worked fine.
Came home to play after work and the (A) button does not work for combat. It works to select things and talk to NPCs, but not to use melee weapon.
WTF??! I have changed controllers, quit the game, restarted the console, teleported out of the dungeon, and NOTHING works… 
I haven’t owned the game for 24hrs and already here we go with the BS.
UNBELIEVABLE. 
If you still have the same problem and you are like me, meaning that you replaced the original sticks with magnetized ones then you might want to try and change the right analog stick back to the original plastic one. The magnet somehow messes with the controller.