The other I have seen is that the audio level from the Pi to the Signalink might be too low to key the VOX circuit on the Signalink.
To fix/try do this: 1.? In a terminal window start the alsamixer 2.? Use the F6 key to select the USB Coder (Signalink)? Mine is Device=2 3.? Use the Up Arrow key to increase the level.? Mine defaults to 46.? Key the transmitter with a program (Tune) and Up Arrow until the rig keys.? Should not need to go higher than 50
If this doesn't fix the problem, then return it to the level you had previously and look somewhere else.