https://gyazo.com/d1cd4f64e5f1402272025e6135749bfe
crash-2019-06-15_01.32.20-client.txt

Everytime I go in my server, which loaded in fine, I go in join and then crash back to Technic Launcher.
Don't know what to do help.

Update SecurityCraft. The version you're using is multiple years old.

Yes, the newest version also works on 1.7.10.

Download the following file, drop it in your mods folder and remove the old SecurityCraft file. https://minecraft.curseforge.com/projects/security-craft/files/2683639