When you are trying to sync one of your songs, it can happen that you receive the following message:
Track data is missing - Sorry, we could not match this track in our catalog - Error code: tc_generic
In this case, what you can try to do is to import in Musixmatch Pro again the release where the song is included.
Here is a step-by-step guide:
Login into Musixmatch Pro https://pro.musixmatch.com
Go to the 'Roster' tab
Select the artist
Select the tab "Music"
Click on "Add missing release"
Enter both your Spotify and Apple Music album links for the missing release. (Please check here how: How to correctly add my album links from Spotify and Apple Music)
Click 'Send'. (If you can't see this button, make sure to scroll down)