Why is my server getting stuck on recvfrom()? (UDP socket) - c

Question

I'm required to make a 'height sensing subsystem' to read the data sent from a moonlander by making a UDP protocol. The client is already set up for me, and is a 64bit executable on linux run by using ./simulator. So I need to make the UDP server in linux to connect with the client.
The client sends readings from many subsystems in the moonlander, but I only need to read one of them, which is the laser altimeter reading that corresponds to the a type specified by 0xaa01, there are other types such as 0xaa##, and 0xff##, but those correspond to different subsystems of the moonlander I assume. The data sent from the ./simulator file is sent through the type, which I then need to decode to find if its the laser altimeter, and then I need to decode the values to convert into distance to find when the moonlander has touched down. I need to read the time first, which has a size of 4 bytes and is an unsigned 32 bit integer, and the laser altimeter reading is 3 unsigned 16-bit integers that correspond to 3 different measurements (as there are 3 different sensors on the altimeter, max height of 1000m, convert by dividing by 65.535 which is UINT16_MAX, and multiplying by 100 to convert to cm). I need to then take those readings, convert them into height, and then acknowledge that we've landed once we've hit 40cm away from the ground.
How do I read the data from the ./simulator file? The problem is that when I run the ./receiver file, it stops working at the recvfrom() function as in my code below. In the instructions, they tell me to connect to port 12778, which works, but I'm not receiving anything.
#include <arpa/inet.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
// Create a UDP datagram socket
int main() {
int fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0)
{
perror("Can't connect");
exit(EXIT_FAILURE);
}
struct sockaddr_in addr;
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET; // use IPv4
addr.sin_addr.s_addr = INADDR_ANY; // bind to all interfaces
addr.sin_port = htons(12778); // the port we want to bind
// Bind to the port specified above
if (bind(fd, (const struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("cant connect");
exit(EXIT_FAILURE);
}
printf("here");
// Listen for data on our port (this is blocking)
char buffer[4096];
int n = recvfrom(fd, buffer, 4096, MSG_WAITALL, NULL, NULL);
printf("Recieved!");
}