TCP connection between 2 raspberryPI - c

Question

I wrote C code to control traffic lights between 2 raspberry Pi, and it works perfectly. However, I have a huge problem: I wrote all the code on my desktop computer and I wanted to change to my laptop. So I changed the IP address in my client, and now the TCP connection fails...
So I run my server.c first, and then my client.c, but after few seconds, I have the message "Connection failed". I really don't understand why, because it worked in my other computer with the same configuration. I give you only the code with the TCP connection.
Here is my code for the connection:
client.c:
/* TCP Variables*/
int sock = 0, valread;
struct sockaddr_in serv_addr;
char *hello = "Hello from client";
char buffer[1024] = {0}; // message receive from RaspberryPI 1
void configurationTCP()
{
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
{
printf("\n Socket creation error \n");
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
// Convert IPv4 and IPv6 addresses from text to binary form
if(inet_pton(AF_INET, "192.168.137.193", &serv_addr.sin_addr)<=0)
{
printf("\nInvalid address/ Address not supported \n");
}
if (connect(sock, (struct sockaddr *)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\nConnection Failed \n");
}
}
int main()
{
// Start Message
printf("test!!\n");
// Enter Start Button
scanf("hey");
configureGPIOs();
launchTests();
// COnfigure TCP connection :
configurationTCP();
}
server.c:
void configurationTCP()
{
// Creating socket file descriptor
if ((server_fd = socket(AF_INET, SOCK_STREAM, 0)) == 0)
{
perror("socket failed");
exit(EXIT_FAILURE);
}
// Forcefully attaching socket to the port 8080
if (setsockopt(server_fd, SOL_SOCKET, SO_REUSEADDR | SO_REUSEPORT,
&opt, sizeof(opt)))
{
perror("setsockopt");
exit(EXIT_FAILURE);
}
address.sin_family = AF_INET;
address.sin_addr.s_addr = INADDR_ANY;
address.sin_port = htons( PORT );
// Forcefully attaching socket to the port 8080
if (bind(server_fd, (struct sockaddr *)&address,
sizeof(address))<0)
{
perror("bind failed");
exit(EXIT_FAILURE);
}
if (listen(server_fd, 3) < 0)
{
perror("listen");
exit(EXIT_FAILURE);
}
if ((new_socket = accept(server_fd, (struct sockaddr *)&address,
(socklen_t*)&addrlen))<0)
{
perror("accept");
exit(EXIT_FAILURE);
}
}