I have a Panasonic unit attached also, and it, thankfully, works fine.
I have tried re-setting everything (took out all batteries, re-booted Telo), but no help.
I have an email into support, but they have been kinda slow lately, so I thought I would see if I'm alone with this problem.
To do a factory reset of the Telo:
Power down the Telo.
Power up the Telo.
1 and 2 come on.
1 and 2 go out and trash and envelope come on
Trash and envelope go out and the bottom row starts scanning to the right
When the scanning stops the Ooma symbol will light up red
Press and hold stop and trash immediately before it blinks.
The Ooma symbol will alternately blink red and blue
The Ooma symbol will turn solid red
The Ooma symbol will go out and 1 and 2 come on
Release the stop and trash buttons.
The Telo will then do another reboot.
To do a factory reset of the handsets:
Turn off handset.
Press and hold the 0 and left softkey, while powering on the handset.