Points to next level

All of them, or just some? One possibility is that you are logged into a different account than originally. Is all of your data still in place? If not, then sign out, and sing back in with the original credentials.

It now says maximum level reached but before was counting down to next level (6)

Please post a screenshot of the Badges page (https://connect.garmin.com/modern/badges). It should be something like shown on the screenshot below, but if you just reached a new level, the progress bar on the right side will be empty, of course.