# Port /dev/ttyUSBx denied
**URL:** https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217
**Category:** General
**Created:** [17 July 2022 13:53 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217 "2022-07-17T13:53:53Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 13:53 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/1 "2022-07-17T13:53:53Z")
Bonjour,
Depuis le passage à la v3 de Node Red , je ne peux plus accéder a mon boitier Rflink, qui est branché sur un port Usb d'un raspberry3b+. J'utilise la palette " node-red-node-serialport" et je suis sous Node.js v16.6 . J'obtiens cette erreur quand je "deploy" :
`"[serialconfig:5fefad5a76dd3e43] serial port /dev/ttyUSB1 error: Error: Error: Permission denied, cannot open /dev/ttyUSB1"`
Est ce que ce problème peut etre lié a la version 3 de Node Red? sous la version précédente v2.x, tout se passait bien.
---
### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [17 July 2022 14:05 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/2 "2022-07-17T14:05:56Z")
> [@PSoy21](#):
>
> I am under Node.js v16.6
Did you change node.js versions when you upgraded Node-RED? If so, you need to do a rebuild of your nodes.
```auto
cd ~/.node-red
npm rebuild
```
---
### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 18:17 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/3 "2022-07-17T18:17:27Z")
Bonjour @TotallyInformation
merci pour votre reponse
J'ai planté node red et quand je l'ai redémarré, je suis passé en version 3, j'ai vu qu'il fallait Node.js v16, donc je suis monté de version. ça fonctionnait toujours pas alors j'ai tout réinitialisé, dont tous mes flows. Est ce que je peux exécuter ce que vous me dites ou c'est trop tard.
---
### Author:  [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)
#### Post date: [17 July 2022 18:53 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/4 "2022-07-17T18:53:49Z")
> [@PSoy21](#):
>
> I reset everything, including all my flows
If you deleted everything, you will not be able to get anything back unless you have a backup.
It is likely that you did not delete the `~/.node-red/node_modules` folder though and that is where the node packages are kept.
When node.js changes major version is is normal for the C++ libraries to need recompiling which is what the rebuild command does amongst other things. The serialport node uses some compiled C++ and so needs rebuilding. It never hurts to run rebuild other than it may take a bit of time on a Pi.
---
### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 20:05 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/5 "2022-07-17T20:05:57Z")
merci pour vos réponses @TotallyInformation
j'ai tout réinstallé, Node red V3 et node.js v16.6.0, j'ai restauré mes flows , j' ai recompilé comme vous me l'avez suggéré, mais j'ai toujours ce problème
```auto
"[serialconfig:5fefad5a76dd3e43] serial port /dev/ttyUSB1 error: Error: Error: Permission denied, cannot open /dev/ttyUSB1"
```
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [17 July 2022 20:27 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/6 "2022-07-17T20:27:16Z")
Is the user running node red in the dialout group?
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### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 20:29 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/7 "2022-07-17T20:29:43Z")
bonsoir @Colin
je ne suis pas très fort dans linux, dites moi comment je peux voir ça s'il vous plait!
---
### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [17 July 2022 20:35 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/8 "2022-07-17T20:35:10Z")
Run the command
`groups`
to see the groups the logged in user is in. If not in dialout then you need to add the user to that group. I always have to look up how to do that. Reboot after fixing it.
---
### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 20:37 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/9 "2022-07-17T20:37:14Z")
```auto
pi adm dialout cdrom sudo audio video plugdev games users input render netdev docker gpio i2c spi
```
ça me renvoie ça . Je vous avoue que je ne comprends pas ce que ça veut dire
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### Author:  [@Colin](https://discourse.nodered.org/u/Colin)
#### Post date: [17 July 2022 20:53 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/10 "2022-07-17T20:53:18Z")
The user is in the dialout group, so that is not the problem. I don't know why you get the error.
---
### Author:  [@PSoy21](https://discourse.nodered.org/u/PSoy21)
#### Post date: [17 July 2022 20:59 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/11 "2022-07-17T20:59:28Z")
Merci quand même, je vais continuer à chercher
bonne soirée 😄
---
### Author:  [@system](https://discourse.nodered.org/u/system)
#### Post date: [15 September 2022 20:59 UTC](https://discourse.nodered.org/t/port-dev-ttyusbx-denied/65217/12 "2022-09-15T20:59:54Z")
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