Here's a cut and paste from a post I made on the 3DR Solo Owners Group on FB. Many others are reporting the same or similar problems.
"Went to the lake today and launched Solo TWICE from a boat. BUT once airborn, I could NOT get the GoPro to start recording. We did follow Me and Follow Me Orbit. Worked great, but no video. ARRRGGGGHHHHH!!!! Any idea what the problem might have been? I just got home and haven't had a chance to troubleshoot. Feeling really disappointed."
For a long while I couldn't get a video feed at all.