Unpair all devices on the echo. If you were sending the receiver to the echo, and now you want to send the echo to the receiver, the default is going to be for the the echo to receive, not to send. Echos are awesome, but very very finicky at times, add in the new BT formats and it's a mess.
I'm assuming you were using the echo as a BT speaker off your receiver and now want to use the echo as a source for your receiver?