LE Start Encryption connection timeout

hi, All

I am developing BLE for our production, but a issue blocks me:

< HCI Command: LE Start Encryption (0x08|0x0019) plen 28

HCI Event: Command Status (0x0f) plen 4

    LE Start Encryption (0x08|0x0019) status 0x00 ncmd 1

HCI Event: Encrypt Change (0x08) plen 4

    status 0x08 handle 64 encrypt 0x00
    Error: Connection Timeout

HCI Event: Disconn Complete (0x05) plen 4

    status 0x00 handle 64 reason 0x08
    Reason: Connection Timeout

HCI Event: Number of Completed Packets (0x13) plen 5

    handle 64 packets 1

Does anyone have some clue why this happen?

Thanks a lot!

Yuanbo

-- 
Janboe Ye