iOS pairing and bonding issue

[user_padm]

I am working on iOS pairing and bonding and connection and disconnection through UART.I am facing issue where pairing is initiated after that the device is getting automatically connected to the device then i am receiving passkey after entering the passkey advertisement in the iOs device is getting turned off and after few seconds i am getting message as disconnected with reason (0x19).I am using the sdk version 2.5.0 with following configurations.

CONFIG_BT=y
CONFIG_BT_CENTRAL=y
CONFIG_BT_GATT_CLIENT=y
CONFIG_BT_GATT_DM=y
CONFIG_LOG=y
CONFIG_DEBUG=y
CONFIG_BT_SETTINGS=y

#Bluetooth security manager protocol settings
CONFIG_BT_SMP=y
CONFIG_BT_SMP_ENFORCE_MITM=y
CONFIG_BT_SMP_SC_PAIR_ONLY=y
CONFIG_BT_BONDABLE=y
CONFIG_BT_PRIVACY=y

output i am receiving :

Received string: scan_off
Scan Off command received
Scanning successfully stopped
pair 7a:8f:5b:ea:8e:14
Received string: pair 7a:8f:5b:ea:8e:14
Pair command received
Address: 7a:8f:5b:ea:8e:14
Cleared bonding info for 7a:8f:5b:ea:8e:14
Connection attempt initiated to 7A:8F:5B:EA:8E:14 (random)
Connected: 7A:8F:5B:EA:8E:14 (random)
Passkey entry requested
passkey 048047
Received string: passkey 048047
Passkey: 048047
Security changed: 7A:8F:5B:EA:8E:14 (random) level 4
Pairing completed. Bonded: 1
Disconnected (reason 19)

[Amanda Hsieh]

Hi, 

Could you provide the sniffer log to help investigate the issue?

Before starting to capture, please try to erase the board before programming and turn off and on the Bluetooth on iOS to delete the bond. 

Regards,
Amanda H.

[user_padm]

Currently i don't have sniffer setup.Is there any other way I can resolve the issue?

[Amanda Hsieh]

Disconnect reason 19 means that the remote user terminated the connection, so the iPhone disconnected for some reason. Could you erase the board before programming, turn off and on the Bluetooth on iOS to delete the bond information, and try again? 

[user_padm]

Did the same procedure,still the same issue .but for android it is working fine initiates the pairing ,connectes to the device,passkey entry the pairining and  bonding will be performed.
Pair command received
Address: 40:13:56:51:ea:17
Cleared bonding info for 40:13:56:51:ea:17
Connection attempt initiated to 40:13:56:51:EA:17 (random)
Connected: 40:13:56:51:EA:17 (random)
Passkey entry requested
passkey 903881
Received string: passkey 903881
Passkey: 903881
Security changed: 40:13:56:51:EA:17 (random) level 4
Pairing completed. Bonded: 1

[Amanda Hsieh]

How do you erase the board?

After testing with the Android phone, did you erase the board before programming again and then testing with iOS? If not, please do it.