Hi Manu,
I've spotted what the problem is. SongSelect, for some reason is downloading the chordpro file as a text file (with the .txt extension). I just checked this with a public domain song that I can test. When I tried this, the file is named: hark-the-herald-angels-sing-mendelssohn-chordpro-F.txt
If you manually change the ending from .txt to a valid chordpro file extension (.crd, .cho, .chopro) OpenSongApp will import it correctly. What I will add to the next release is a check for importing a song that has ends with .txt but has -chordpro- in the filename and treat it as a chordpro file.
I've attached what I see before the fix (using the file with the wrong extension) and what you will see if you manually change the file extension of the file before importing, or wait until the next app update (the fix is ready to go, but I have quite a few big changes with the metronome and new drummer feature to finish)

