Videos and audio not working/playing

I have an iphone 6 that I am trying to fix, and it has a problem where it would not play any videos(it would say an error has occurred for any video tried to play through youtube safari ect...) and audio would not work either through things like phone calls, on speaker or headset mode. I first tried erasing all content and settings, which did nothing. I then tried disconnecting the battery, pressing the power button a few times, then booting it back up. This kinda fixed the problem, as when I tried to play a video, no error would occur, but it would just load the first frame and never actually play, and the audio is now working through the headset, but not on speaker. Does anyone know what is causing this? thanks!