I just bought my Lumia 535 3 months ago. Recently, sound problem happened. I din't do anything, I just left it there, then, all sounds lost. No ringing, no app sound, nor even vibration. I've checked the sound setting, volume is still at max level. The only way to fix this is reset the phone (turn it off and on again by holding the POWER and VOLUME DOWN button).
This problem is very annoyed. Please help me to fix this. Thank you so much for your help.