Unable to read Heart Rate Measurement and do not see any Notification on Xiaomi Band 8 Using gatttool

[timothy_lim]

HI Everyone,
I'm having trouble reading heart rate data from my Mi Band 7 using the linux command, "gatttool". I have connected to the device via Bluetooth and discovered the relevant characteristics which are
- 0x180F which is the Heart rate service
- 0x2a37 which is the Heart Rate Measurement which properties is NOTIFY.

What I have done so far by trying the commands inside the gatttool
I identify the Heart Rate Service

primary
attr handle: 0x0039, end grp handle: 0x003c uuid: 0000180d-0000-1000-8000-00805f9b34fb

Then I read the characteristics for Heart Rate Service and could see 0x2a37 which properties is NOTIFY

char-desc 0x0039 0x003c
handle: 0x0039, uuid: 00002800-0000-1000-8000-00805f9b34fb
handle: 0x003a, uuid: 00002803-0000-1000-8000-00805f9b34fb
handle: 0x003b, uuid: 00002a37-0000-1000-8000-00805f9b34fb
handle: 0x003c, uuid: 00002902-0000-1000-8000-00805f9b34fb

i tried reading Heart Rate Beat Data but I cant

char-read-hnd 0x003b
Error: Characteristic value/descriptor read failed: Attribute can't be read

I enabled the notification to 0x2902 but Cant see any notifcation

char-write-req 0x003c 0100 --listen
Characteristic value was written successfully

Please advise on how to read the heart beat data and how to receive the notificattion. Is there a need to input authentication for this?

If so how to achieve this?