Why doesn't the mss, iptables rule work?

Question

linux

the rule itself
iptables -A FORWARD -s 0.0.0.0/0 -p tcp --sport 443 --tcp-flags SYN,RST SYN -j TCPMSS --set-mss 50
this solution works locally, but why doesn't the forward work?

Answer 1

-A INPUT

why should he work?