The best advice was said earlier. Open battery box on controller and disconnect battery. Wait for 5 minutes and reconnect battery. This will reset your controller. You are having connection problems with controller. Every time I update, I am having this problem. Make sure you open 3dr app first and then connect with solo app. Happy flying. This should work.
The OP already completed the ultimate "fix" - he exchanged his Solo and the new Solo works. Before that,
as he stated in this thread, he did remove the controller battery, and did so much more. It
seems that re-pairing would have done the trick on the original Solo, but who knows?
It helps though, to give clear advice to those in need. In your post, what is the "3dr app" as opposed to the "solo app"? I'm not certain what you mean, and it doesn't matter to me as all 3 of my Solos have always connected and always "worked", but new users may be wondering the
whats/wheres/hows of a
3dr app vs. a
solo app.
The details of the start-up procedure that I have always used, which is frequently different from what other users may recommend, is in this thread:
waiting for solo
The difference in my procedure may be that (hopefully)
the instructions are clear and use the correct nomenclature, AND the sequence has
always worked for me, every time, on every Solo I own. As always... YMMV - but I don't know why it would.