Galaxy S4 blutooth device paired but the app to use it cannot connect to the device.

I have the galaxy s4 and I'm trying to connect a blutooth device sometimes I can pair it to my phone and others I cannot, either way when I trying to add the device under the app you download to use the device with the app con not find or connect to the device. Please help!?

What Bluetooth device are you using and what app is giving you the problem?

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Welcome to Android Central! What kind of Bluetooth device are you trying to connect? I also don't understand the second part of your question--you're trying to add the Bluetooth device to an app that you downloaded?

Yeah, what kind of BT device is it and a little more info about the device/app would be greatly appreciated.

Sent from my Resurrected T-Mobile Note 3