If you are experiencing difficulty pairing your mobile phone with your Jawbone, please make sure that your Jawbone is OFF and you have activated your mobile phone's Bluetooth function when you begin a pairing session. Also, ensure that your phone and Jawbone are within one yard (3 feet) of each other.
When you are ready to begin your pairing session, press the Noise Shield Button on the Jawbone (where it says "Jawbone") for a full three seconds until the LED indicator light alternately flashes red and white. Then, you can search for the Bluetooth device from your phone.

Once you have set your phone to search for Bluetooth devices and your phone detects the Jawbone, you have to "add" the device to your phone. Consult your phone's instruction manual for this process. A common issue occurs when a customer tries to pair the Jawbone without "adding" the phone, having only made their phone discoverable.
It's at this point you should be prompted for the Pass Key. Enter 0000. Be certain to enter zeroes and not the letter "O".
Another thing you may want to try is resetting and re-pairing your Jawbone. If this does not resolve the issue, you may want to perform a soft reset on your phone. Please consult your owner's manual for instructions regarding how to perform a soft reset. Generally, this is a secure process. You should not lose any information that you have stored on your phone. However, it is always a good practice to back up your information in the event you inadvertently delete any contact information, photos, ringtones, etc.
(Note: You may need to re-pair your Jawbone after you perform a soft reset on your phone.)