The Fitbit Community is a gathering place for real people who wish to exchange ideas, solutions, tips, techniques, and insight about the Fitbit products and services they love. By joining our Community, you agree to uphold these guidelines, so please take a moment to look them over.
Having the same issue with Running / Biking. Everything is synced properly, but when I start my exercise I get a "Check Fitbit App" error. I fix it and then it works, but stops again for no reason.