"FML" Issue

[coral gazelle]

I previously had a perfect "Roguelike adventures and dungeons" server going, and I backed up the server and loaded a new instance containing the second version of RAD. I downloaded it off of curseforge and swapped the server to rad2, but now it's saying something about missing files fml, yet I can still join the server, is there actually an issue I'll run into? EDIT: it's just a red x that pops up in my server listing

[flint wedge]

If you can still join despite the X then its not an issue

i have this on my server and im able to join