HTC One M9 unable to use phone audio on any bluetooth device

[AC Question]

The contacts will load but when I try to make a call, it doesn't connect and I get a message saying that the bluetooth isn't connected. I have un-paired the two and paired them back. I have deleted the phone from my car bluetooth list and reinstalled it but it still doesn't make calls. I've tried going into the bluetooth settings to turn on phone audio for any device but it doesn't allow me to check it. Has anyone else experienced this issue?

 

[B. Diddy]

Welcome to Android Central! What model year and make/model is your car? Is the phone also connected to some other Bluetooth device, like a smartwatch?

 

[hm_crespo]

I am also having the exact same issue. I still have not been able to track down which app is the one causing this conflict. I have also done a factory restore and that seems to have worked for a time but the issue started again. It may be unrelated but... Have you changed the themes? I think that's one of the last things I did before it stopped working. Also restarting the phone "fixes" the issue for one pairing, after the bluetooth is disconnected it will no longer allow to use phone audio. I have gone into the settings for the "Paired Bluetoth devices" and I am unable to check "Phone audio". It is not grayed out but it doesn't work either. Any ideas?
This is HTC One M9
Android 6.0
Patch Lvl Dec 1, 2016
Sense 7.0
Software # 3.37.605.19

 

[hm_crespo]

It's too bad that that there has been no activity on this post. This issue is driving me crazy, I hate to have to restart the phone every time I get in and out of the car just because the bluetooth wont sync. That being said, I have another clue into the issue. Today I was using the bluetooth in the car while on a phone call and transitioned to my Jawbone Icon when I exited the car flawlessly. I turned off the car, turned on Jawbone (so there wouldn't be a conflict of the Jawbone trying to connect to the phone while it was still connected to the car) Immediately the Jawbone connected and I was able to carry on with the conversation. I was really happy about this. However, when I was done with my phone call I turned off the Bluetooth and turned off the Jawbone. About an hour later I received a video through Whatsapp and when I played it there was no volume. When I pressed the volume button on the phone the volume bar had the Bluetooth symbol!!! The Bluetooth had been off for quite a while now and there where no Bluetoth devices present.
Hopefully this gives some insight into this issue that will help resolve it. Thank you very much!

 

[John Gauthier1]

Having this exact issue- I have tried to troubleshoot this with several bluetooth devices- PLT-Voyager, BSH10, Streambot mini, LG-Tone. All of them are functioning fine on other devices, but on the HTC it will not allow me to select them as the audio device for the phone. I am about ready to reset the damn phone to see if that will fix, but I thought I'd poke around to see if anyone else is having this problem

 

[Alex Deadmond1]

I am having the same issue
HTC One m9
Viperonem9 5.1.0

I have tried wiping / reflashing and still haven't resloved the issue.

this is super annoying I hope someone finds a fix soon