Here is the crash log, with the relevant bits being:

net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from Pixelmon GUI Blocks (pixelmon_gui_blocks)
Caused by: java.lang.NoSuchFieldError: TMs

unable to find resolution online, and the version of Pixelmon mentioned on the mod page doesn't exist on Curseforge