Mute button does not function

The mute button on my iPad has stopped functioning. What must I do to solve this problem?

By mute button do you mean the side switch?

Have you tried going into settings and selecting it to lock rotation and then back to mute?

I find powering off the iPad and switching it back on again solves all bar the most complex of iPad woes!

Yes, I meant the mute side switch.
In settings I don't find any option for lock rotation or mute.
I have tried to power off & on the iPad, but there is no change.

What version of iOS are you running?

A while back an update was released to enable you to choose the function of the side switch.

It's under; Settings > General > Use side switch to - and then there's the option to use it to mute or lock rotation.