how i can fix linux Debian nf_cotrack

I have problem with my linux router (Debian) when i run MTR, it always had loss in 1 hop it in my server then my friends tell me is because my nf_cotrack full, i have been up max_cotrack but that just for temporary i read nf_cotrack can be flush and i try but got some error

can anybody help me, thank and im sorry my write is not good enough :D nf_cotrack