In AWS EC2, I start a Classical Load Balancer in front of EC2 instance (security group of EC2 instance is launch-wizard-3). i want to change the inbound rule of Security Group of EC2 instance . A security group for Classical Load Balancer (it's name is my-first-load-balancer-sg) was also started. when i am changing source of an inbound rule of launch-wizard-3 to the my-first-load-balancer-sg, following error is prompted. I tried many times to solve it, but i couldn't.

the error- You may not specify a referenced group id for an existing IPv4 CIDR rule.

the inbound rule as follows

(type-HTTP, protocol-TCP, port rang-80, Source type- Custom, Source- my-first-load-balancer-sg(what i want to place) )

Please help me~! Thanks!