Hello,
I have been using multiple iPhones - 4s/5s/6s and iPhone SE with my 2012 Mini Cooper S for the past 11 years+. I use the original Mini Aux/USB to iPhone 4s cable, which looks like - https://i.ebayimg.com/images/g/f5wAA...GSc/s-l960.jpg
Since Dec 2015, I have been using the above with the original 30-pin to lightning adapter - https://i.ebayimg.com/images/g/k2oAA...zM/s-l1600.png

All of a sudden the iPhone tells me that the "accessory is not supported" and I cannot use either 6s or iPhone SE anymore with the car.
I suspect a problem with the car set up. I once resolved a similar issue by re-plugging the audio system fuse. Is there a better way to address this? Perhaps, an easier way to reset the audio system?

Thank you!

 

Updates:
I re-plugged the fuse but it didn't make a difference. The radio display went off when I unplugged the F5 fuse. After a few mins when I plugged it back, I still had the same issue.

Any ideas?
Thank you!

 

Perhaps the adapter has failed? My original Mini cable was acting up and not always showing “iPod” in the menu, and sometimes getting the same error as you on the iPhone, so I switched to the Tune2Air cable to use the Bluetooth connection. I’ve been using the Bovee Tune2Air with my iPhone XS and now my 15 Pro for the past 3 years without issue.

 

As far as I know this message can appear in a few cases:

1. Dirty lighting port
2. Out of date software
3. Not MFI certified or faulty accessory

You are saying you tried it with two different phones, so it's hard to believe both would have ports issue, but I'd start with that nonetheless as it's the easiest. Try to remove any lint that accumulates in lightning ports over time.Restarting phones and making sure sure you are running latest iOS also a must.
If the above doesn't help it leaves #3 as the most probable issue. And since you are saying it did work previously it's most likely that 30-pin-to-Lightning adapter is acting up. If you can get your hands on some old iPod or iPhone with original 30-pin connector I'd test the Y-cable to rule it out. If still nothing then replacing adapter or trying one of the bluetooth dongles similar to Tune2Air as mentioned by @njaremka. I too have successfully used one of those in my 2012 R56S for several years before I fitted CarPlay enabled stereo inside the speedo.

 

Hello!
"30-pin-to-Lightning adapter is acting up" seems to be the real issue. I tried again with an older 30 pin to lightning adapter which supported sound and charging for about 30 seconds before flashing the same "Accessory not supported" message. I have used the newer (and original) 30-pin to lightning adapter for the last 6 years without any issue. It seems a case of wear and tear. Since this is now discontinued, I am going to buy a new Aux+USB t o lightning Y-cable.
I explored a few solutions like Tune2Air but the wired option serves the dual purpose of charging and audio. TY @maccoder and @njaremka !!

 

I use a MagSafe mount to handle the changing side. The combination of the MagSafe mount and the Tune2Air make changing and music pretty seamless for me.

 

Thank you, @njaremka

 

I bought the following Y cable, amazon.com/dp/B099QHKD4W?th=1

It works absolutely fine, charges and plays audio. However, I only see the Aux & USB options on the display port now. Earlier it used to transition to IPOD and would show the audio/video metadata e.g. a YouTube video name or even a URL in case I played a video on a website. I guess that's a shortcoming with non-Apple equipment.
I have a few questions for @njaremka -

1. I presume your car display shows the metadata if you see iPod listed there. Am I right?
2. Have you explored playing YouTube audio on the car stereo using its (Airplay and) Bluetooth devices option? I once saw the option and wondered if you need a separate Bluetooth device.

Thank you!

 

Yes, the car display will show song data, and the steering wheel controls will change tracks. I have not tried YouTube audio. I listen to Apple Music almost exclusively. It will pick up audio from other sources, like instagram or videos, so YouTube would probably also play over the air to the device.