Error connecting to bluetooth headset

[gomes_tisystem]

Please tell us some basic information before asking for help:
Model Name: ASUS_X01BDA
Firmware Version: JP-17.2018.2007.428 / Max Pro M2
Rooted or not: Not
Frequency of Occurrence: constantly
After updating to version 10 of android the device in pair with my bluetooth headset, always returns the following error, it was not possible to pair with C1 because of an incorrect PIN or password.
====================================

[gomes_tisystem]

So friend the version is WW and not JP the update procedure was via memory card.

[gomes_tisystem]

The update procedure was done following the instructions on the ASUS website following all the recommendations

[gomes_tisystem]

The installed version is the one indicated by the website the problem is this bug with some Bluetooth headphones

[gomes_tisystem]

I fixed the version, but the problem still remains with Bluetooth headsets that worked on version nine of Android.

[Christine_ASUS]

Hi gomes.tisystem
Thank you for your reply.
1. Which earphones brand and model are you using? Can other bluetooth earphones model work with your device?
2. Can your earphones work with other phone in Android 10?

If the situation remains after performing the Factory Reset, you may follow the steps below as 10 to 9 downgrade steps to use your current earphones' model.
1. Download "MaxProM2_downgrade_to_9" and then put the image file into the root directory of the MicroSD card.
https://www.asus.com/br/Phone/ZenFone-Max-Pro-M2/HelpDesk_BIOS/
2. Insert MicroSD card into phone and then power off the device.
3. Long press with "Power" key and "Volume Down" key together and stop after feel the vibration to enter Recovery Mode
4. Use "Volume Down/Up" key and press "Power" key to choose "Apply update from external storage"
5. Select the downgrade file
6. When the updating process is done, Choose "Wipe data/factory reset" and tap"Yes" to perform the master clear.
7. "Wipe cache partition" > "Yes"
8. "Reboot system now" 

#Android 10 to Android 9 Guide 
https://www.asus.com/support/FAQ/1042349