Loadiine doesn't have perfect compatibility, read the compatibility list on
https://wiki.gbatemp.net/wiki/Loadiine_compatibility_list and make sure you follow the steps to get it working (on Loadiine GX2 0.3 don't use any update data or NNID and it should work according to that but if you have a NNID linked you need to use the Smash Bros mode)
But these days it's recommended to use WUPInstaller instead, it has perfect compatibility, faster load times and online support.