To fix the problem you can use a hands free headset or make sure headset plug has three rubber rings instead of two (the most common). The third rubber ring is for headphones which have a microphone in them for handsfree. The phone is not working with the other headphones because it is trying to recognise a microphone as well. My phone started to not recognise my headphones yesterday. I had been using the same headphones with this phone for months. I think the problem is due to a software update a few days ago. I was told I should try headphones with a microphone as well (3 ribber rings) by my father who used to fix Sony euipment and it worked. Hope this helps.
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