setsockopt: Protocol not available [Solved]

Problem code:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Solution:

if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt))) 

{ 

perror("setsockopt"); 

exit(EXIT_FAILURE); 

}

Ref.: https://stackoverflow.com/a/59807281/4064166