# IMPORTANT Error accessing device

**URL:** <https://forums.balena.io/t/important-error-accessing-device/368182>\
**Category:** balenaOS\
**Tags:** network, raspberrypi4\
**Created:** [June 20, 2023, 3:14pm UTC](https://forums.balena.io/t/important-error-accessing-device/368182 "2023-06-20T15:14:08Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![RURU](https://avatars.discourse-cdn.com/v4/letter/r/ea666f/32.png) [@RURU](https://forums.balena.io/u/RURU)\
**Post date:** [June 20, 2023, 3:14pm UTC](https://forums.balena.io/t/important-error-accessing-device/368182/1 "2023-06-20T15:14:08Z")

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Bonjour,  
J’ai cette erreur qui lorsque j’essaye de me connecter à mon adresse url public pour paramétrer mon lecteur dynamique.  
Voici l’erreur que j’ai :

We encountered an error when reaching this [balena.io](https://balena.io/) device:

UUID 60034b7916cfed7c60e203a8eb27b3ca

`tunneling socket could not be established: 500`

One possible reason is because nothing is listening on port 80 on the device.

POURTANT, j’ai ouvert tous les ports et j’ai suivi la technique donnée par BALENA ( voir en pièce jointe)  
Merci d’avance, je suis vraiment bloqué dans ma configuration

 ![EXIGENCES PORTS BALENA OS](https://global.discourse-cdn.com/balena/original/2X/4/470be7af575887ac0ff1206e0e75cc79fa7e996d.png)

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<div class="post-metadata">

**Author:** ![RURU](https://avatars.discourse-cdn.com/v4/letter/r/ea666f/32.png) [@RURU](https://forums.balena.io/u/RURU)\
**Post date:** [June 20, 2023, 3:15pm UTC](https://forums.balena.io/t/important-error-accessing-device/368182/2 "2023-06-20T15:15:09Z")

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[https://60034b7916cfed7c60e203a8eb27b3ca.balena-devices.com/](https://60034b7916cfed7c60e203a8eb27b3ca.balena-devices.com/)

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**Author:** ![alanb128](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/alanb128/32/2839_2.png) [@alanb128](https://forums.balena.io/u/alanb128)\
**Post date:** [June 21, 2023, 12:48am UTC](https://forums.balena.io/t/important-error-accessing-device/368182/4 "2023-06-21T00:48:25Z")

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Hello, that error usually means that the service (your “dynamic player?”) you expect to find on your public URL is not listening on port 80 on the device. You can map the port the service is using to port 80 on your host by using the `ports` feature in your docker-compose file: [Compose file version 2 reference | Docker Documentation](https://docs.docker.com/compose/compose-file/compose-file-v2/#ports) For instance, if your service is using port 5050, you would add a `ports:` entry of `80:5050` to map it to the public URL.

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<div class="post-metadata">

**Author:** ![RURU](https://avatars.discourse-cdn.com/v4/letter/r/ea666f/32.png) [@RURU](https://forums.balena.io/u/RURU)\
**Post date:** [June 21, 2023, 10:08am UTC](https://forums.balena.io/t/important-error-accessing-device/368182/5 "2023-06-21T10:08:00Z")

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Merci pour votre aide je vais voir comment faire pour que ce la fonctionne.  
Malheuresement j’ai un probleme lorsque je pousse le code sur balena le lecteur dynnamique ne fonctionne pas ( ecran noire) et il y a des codes erreurs suivants :  
2023-06-21T12:03:30+02:00 main npm ERR! missing script: start  
2023-06-21T12:03:30+02:00 main  
2023-06-21T12:03:30+02:00 main npm ERR! A complete log of this run can be found in:  
2023-06-21T12:03:30+02:00 main npm ERR! /root/.npm/\_logs/2023-06-21T10\_03\_30\_570Z-debug.lo

et aussi :

2023-06-21T12:03:30+02:00 main npm ERR! missing script: start  
2023-06-21T12:03:30+02:00 main  
2023-06-21T12:03:30+02:00 main npm ERR! A complete log of this run can be found in:  
2023-06-21T12:03:30+02:00 main npm ERR! /root/.npm/\_logs/2023-06-21T10\_03\_30\_570Z-debug.lo

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<div class="post-metadata">

**Author:** ![alanb128](https://sea2.discourse-cdn.com/balena/user_avatar/forums.balena.io/alanb128/32/2839_2.png) [@alanb128](https://forums.balena.io/u/alanb128)\
**Post date:** [June 28, 2023, 1:58am UTC](https://forums.balena.io/t/important-error-accessing-device/368182/7 "2023-06-28T01:58:36Z")

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Hello, that error seems like you might not have defined a start script in your package.json file or your project does not contain a server.js file. Can you post more information about your project or a repo link if it is public?