u/RTxMAFIA

Permanent Fix is to turn off Bluetooth on your Xperia phone before turning on audio Speakers like Bose Soundlink Flex or Headphones like Sennheiser then after 5 seconds turn on Bluetooth on your Xperia Then you won't get this error.

**If you turn on Xperia Bluetooth before you turn on Bluetooth speaker then you will keep getting this error. Sony Xperia 5 mark 4 wrong passkey or pin" message while pairing a bluetooth device.Hope this helps.

If you have done connecting to Bluetooth speaker like Bose Sound Link or Momentum 4 without following above step then you will get this message Bluetooth wrong passkey or pin"

Follow below steps and keep the above Permanent Fix like Rule of Thumb so this won't happen again To Solve this bluetooth issue problem you need to turn off bluetooth first then Clear Bluetooth Cache (Android):** 

**Go to Settings > Apps > Show System > Bluetooth > Storage > Clear Cache/Data. Then turn on bluetooth device again.

Problem solved The important step to to remember is to turn off bluetooth on Xperia first before Connect it to Bose Sound Link Speaker. Then only above solution works. I have suffered from this problem for 1 day after that I have figured this out. Upvote this post if this helps Thanks!**