Cannot purchase items from shops

I am having this issue in the Steam version of the game. I can't purchase items from vendors. Whenever I press the button to confirm, the button flickers but no purchase is actually made. I have tried traveling to other locations and trying to shop there, but the issue persists. Not sure what I can do to fix this.

Edited to add: I was able to solve the issue. I am playing with a controller and the button was not being recognized for some reason. I had to disconnect the control and use the keyboard for a bit, and reconnect the control again. I can now shop without any issues. I am not sure what triggered this issue, but will update if it happens again.