Earphone stopped working

I have a Samsung Tab S, and recently, my earphone (one that came with the tablet itself) stopped working. Earlier, when I plugged the phone, the main speaker's device stopped and only the phone worked, as any standard device, when you plug a phone. But now, when I plugg earphones (tryied two types already), the main device speakers don't turn off, but the earphones icon appears in the notifications bar. Lately I dicovered that on the recomended app youtube, the earphones work properly, but when I close that app, the entire system switch to the main speaker's device and the phones stop working. On another samsung app that plays music, occcur the same thing as youtube. It seems now that the earphone stopped to work globally in the system and just work on some apps. Any idea on how to return to the standard earphone state?