Error process
When starting the docker container nginx, it cannot be started and always reports an error, as shown in the figure below

After reset gateway, iptables are activated, docker chain Settings are not updated!
The solution
Restart the Docker service to cause the latest Settings to be added to iptables.

systemctl restart docker

When you look at the iptables rule, the docker chain has been reset

iptables -L
iptables -t nat -L