If the button does not work or gives problems, we must check several possible problems until we find the solution.
Smartphone well placed
The first thing to check is that you have placed your smartphone properly inside your Heromask. To do this, make sure that the smartphone is centred with the screen facing the lens and leaving behind the smartphone the fastening tab as shown in the following video.
Button check
If this has not solved the problem and the button still does not work, check that the rubber touch is correctly installed/placed inside the headset. 
If it is not installed, there should be a spare in your Heromask pack. The next step is to install this spare as shown in the video below.
Screen protector
If none of the above steps solved the problem, it is possible that you have installed a screen protector that is too thick and does not allow the button to act properly. If this is the case, the best thing to do would be to try with another device that does not have a screen protector installed, so that if it works on the device without the screen protector, we will have found the problem. If this was the problem you can remove your screen protector so that the button can act and play normally on your smartphone.
Contact us
If none of the above steps have solved the problem, please contact our customer service team. Tell them the steps you have followed and they will do a final check with you and if the problem persists, they will send a new Heromask to your home free of charge.