If your jigsaw pieces no longer "snap" together with a click sound, it could be that your sounds are muted (turned off).
If you have an older iPad model, check that the switch on the side of the iPad has not been moved in to the "mute" position. Do you see an orange dot ? If so, switch it the other way.
The newer iPad models do not have a mute button on the side of the iPad. On these models the mute button is in the Control Center panel that slides up from the buttom of the screen. Slide up the Control Center, check the mute button. If the bell symbol has a line through it, then sounds are muted. Tap to enable the sounds.
If that does not resolve the problem, check the Jigsaw Box app Settings menu. Press Settings and in the settings tab, make sure the option called "Click on Connect" is turned on (ticked). Finally, it could be the iPad audio routing. Please try re-setting this, by plugging in some headphones in to the headphone jack. Can you hear sounds through the headphones? Try plugging them in and out a couple of times, to reset the audio routing.
If none of the above checks makes the sound come back, please cold re-start your iPad. Sometimes the sounds settings on the iPad need to be reset, and a re-start of the iPad will do this. To Restart your iPad follow these instructions:
How to restart your iPad
It's a good idea to restart your iPad every few weeks to keep it running smoothly. To do this hold in the sleep/wake button at the top of the iPad for a few seconds until you see the message "Slide to Power Off" in red. Then slide it, and the iPad will switch itself off. Wait a moment, and then press the sleep/wake button again to turn the iPad on again.