Sound not working on my BlackBerry Classic

My sound volume is all the way up and notifications in settings is normal I have never have had any problems with the sound or volume before. My daughter was watching a video when she handed me back my phone the sound was not working.
Am not sure how to fix it I have turned the phone off and on a few times now.
Thanks for any help.

Posted via CB10

I somehow have the same problem with videos from What's App. No sound. A restart always helps but that can't be the solution.

Posted via CB10

Try to reset the phone it usually does the trick for me.

how do I do a reset on my blackberry classic?

Hold down both volume buttons for 20 seconds