Not the same but a similar problem. My Android tablet was able to upload today’s track, but it didn’t show up in raceqs.com. It went fine with tracks that I had taken from my previous sailing trips, with the same equipment and setup. I then sent the track to myself via email, which gave me a .csv file. When I tried to upload that, I got the “unrecognized file format” message. I tried the same with an older track, and interestingly enough it gave me the same error, even though the upload of that older track had been successful originally.
I have attached one of the csv files that are causing the unrecognized file format error.