Powerline Bridge for and U-Verse

We have solar panels that used to use a wifi extender to provide information from the panels to the solar app managing them. When the extender had issues (still had low signal), the solar company (Stellar Solar) came out, reviewed the connections, and installed a power line bridge to provide the signal through our power lines. This was yesterday.

They plugged the power line bridge into the wall, then plugged the modem power brick into the power line bridge. They also connected the power line bridge to one of the ethernet ports on the modem.

Today, our U verse keeps freezing up, making most HD TV unwatchable. We can still watch low def (horrible to view). 

Is this a known issue? I searched on it and saw various discussions, but I didn't see what we need to do to get our u verse back to normal. 

Would plugging the power line bridge into a different physical outlet, then plugging it into the ethernet connection on the modem help? Or is there another remedy? 

Thank you for any help and advice!