no bluetooth signal from receiver

Hey Guys, This is my first post. apologies if I am not communicating clear. i have recently purchased an old SLS QG-500AVR AV receiver and some Yamaha home theatre systems from FB marketplace. He is legit. the subwoofer is working good, I have tested with Bluetooth adapter and the buttons on AV...

I no longer can pick up a Bluetooth signal from my Yamaha audio receiver or any AppleTV devices. I recently changed my internet provider a few weeks ago. Why would I loose these signals and what can I do to fix this issue.