If your speaker fails to connect to your phone over Bluetooth, try the following:

• Make sure your speaker is turned on and paired to the controlling device — press Bluetooth button (located at the rear of the speaker) until the source button at the front pulses Blue. Check the Bluetooth settings list on your mobile device to see if your speaker is listed.  
• Move your speaker closer to your phone as it might be out of range.
• Move your speaker and your phone away from other wireless sources that may be causing interference.
• Turn your speaker off, then back on again.
• Turn your phone’s Bluetooth setting off, then back on again.