Unreachable error when I try to do the arduino Tutorial light switch

  • Arduino Uno with DFrobot ethernet shield (Usb Connection)

  • Dashboard : Web /

  • Os : Win 7


I’m trying to do the light switch. I have completed all steps before I click to “add actuator”, but I get a “Connection error” and then I have an “Unreachable” on the light switch widget. I’m under a school network… but port 8442 and 8181 are open.

I could pass the first phase to get the arduino dashboard, but after, I lost the connection to the arduino when I try to do the tutorial. Televersing is working. Command “cayenne-ser -c COMxx” seems to works correctly.

Could you tell me if there is something to do ?

Hi @florent.delage,

Are you able to post the output that you are getting in your serial monitor? Also, is your Arduino online and showing as connected in Cayenne when you are trying to add the widget?


At the first attempt, yes the arduino is online (when I get the dashboard), but, when I shut down the command for televersing, I can’t get back online

Do you have any solutions ? I don’t have any ideas which kind of Test I could do

Hello @florent.delage,

Could you help us to understand what you are doing here that is sending you offline? I understand that televersing == uploading, but I don’t understand what you mean by ‘shut down the command’. If you would like, post more detail in French! We have many French speakers in the company (our head office is in Paris!), and they can help me to interpret your detail and find a solution here. Thanks for your patience.

Thanks you :slight_smile: Here is what I do :
1/ USB Connection of Arduino
2/ Upload of Get Started Code in Arduino with Arduino IDE
3/ In CMD “cayenne-ser -c COM14” command

Ok I’m on the Dashboard. Now :
1/ In command window CTRL+C to stop the command
2/ Upload of Code of light switch in Arduino with Arduino IDE
3/ Plug components on Arduino card
4/ Option selection (Pin, Icon…)
5/ In CMD “cayenne-ser -c COM14” command
6/ “Add Actuator” > Communication Error

Other Students in my class have the same problem. Is there another port than 8442 which need to be open ?

Et un complément en français : nous sommes plusieurs à avoir suivi le même tuto, la même procédure. Nous avons tous eu la même erreur. Les montages sont corrects, vérifiés par le prof. Nous ne savons où chercher ni ce qui pourrait bloquer… sachant que le 8442 est normalement ouvert.

I notice you said students, are your in a environment with a strict firewall? Port 8442 may be blocked.

Yes, We are Under a school private network. The lan admin have opened 8442… but it’s still not working. Is there a GPO or another firewall rule which could block ? We don’t know where the problem come from.