I have no issue. Are you doing the following?
// Uncomment the following line to enable OOB pairing. Change oob_tk below to the desired key.
// #define OOB_PAIRING
// Uncomment the following line to enable passkey pairing. Change passKey below to the desired key.
You may want to "unpair" or "forget device", depending on what phone you are using, before you go through the whole discover-and-pair cycle again.
Btw, you may want to upgrade to 2.2.2.
Yes, i use iphone6 with lightblue to test, should i must upgrade to 2.2.2 to fix this issue?
That will be a good idea.
Make sure to check if the 20737S device is showing on the device list in your smartphone bluetooth settings. This will cause a problem as it will not attempt to pair again. You need to "forget the device" for 20737S and attempt a fresh pair. For instance, in an iOS device go to Settings->Bluetooth->My devices and select the information for the hello_client device->select "Forget This Device". Then using LightBlue when you select the hello_client device it will pop up the option to pair or not. Hope this helps.