LOOT will tell you of basic conflicts in your load order and it may tell you if you require any patches for major mods. Check out this video if you want more information on LOOT. It integrates with Vortex so you will have to add it from the Vortex dashboard after you install it. I don't know how much knowledge you have, so I'll try and explain it simply just in case :) LOOT isn't a miracle program that can magically solve all your problems, but if you don't have it installed, I fully recommend that you use it. Additionally, make sure your Skyrim SE is fully updated and that you have the latest version of SKSE (I know it's basic stuff but it's best to be sure).
Make sure you have Address Library installed correctly, as MFG Fix requires it. I'm not entirely sure but this error sounds like it has something to do with the mod MFG Fix.