|  | 256 |  | 
          
            |  | 257 | ===== Troubleshooting ===== | 
          
            |  | 258 |  | 
          
            |  | 259 | 1. "SerialException: Device reports readiness to read but returned no data" | 
          
            |  | 260 |  | 
          
            |  | 261 | ROS will not be able to communicate with serial if there is another service using the port, i.e. Serial Monitor | 
          
            |  | 262 |  | 
          
            |  | 263 | - Use lsof to check with programs are using the port `lsof /dev/ttyACM0` | 
          
            |  | 264 | - Kill the program that is using the port `kill {PID}` | 
          
            |  | 265 |  | 
          
            |  | 266 | 2. "socket.error: [Errno 48] Address already in use" | 
          
            |  | 267 |  | 
          
            |  | 268 | Flask server was not properly stopped before starting it again | 
          
            |  | 269 |  | 
          
            |  | 270 | - Close the connection `sudo fuser -k 5000/tcp` | 
          
            |  | 271 |  | 
          
            |  | 272 | - [https://stackoverflow.com/questions/34457981/trying-to-run-flask-app-gives-address-already-in-use More Info] |