check the load order of your mods if any of them order themselves above the core game files on the launcher mods screen you have to manually edit a specific line of code in the XML or download fixed launcher mod (fixed launcher mod works for some people didn't work for me I just got rid of the mods that get out of line.) as for the specific line of code I don't remember what it is I never did it but a few of the mod authors tell you how to do it if you run into that issue on their descriptions page