Hardware The + button on the right Joy-Con is not responding.

[Mexicangamer]

The "+" button only works if I press it hard.

What I've already done is clean the main board with isopropyl alcohol; it works again for about an hour, but then the button becomes unresponsive again.

 

[BigOnYa]

Ok. Thanks for your info.

 

[thesjaakspoiler]

The actual contact is inside that gold colored metal button.
Just wiping it probably won't have much effect.
Although the outside might be gold plated, sometimes on the inside corrosive metals are used.
There probably is dirt/corrosion inside it.
You could try to flush some alcohol through it with a syringe but replacing it would be the best option.