# \[APP\]\[Pro\] Viessmann - Make your heating smart

**URL:** <https://community.homey.app/t/app-pro-viessmann-make-your-heating-smart/116744>\
**Category:** Apps\
**Tags:** app, homey-pro, community-app\
**Created:** [September 26, 2024, 12:33pm UTC](https://community.homey.app/t/app-pro-viessmann-make-your-heating-smart/116744 "2024-09-26T12:33:22Z")\
**Posts on this page:** 1\
**Showing post:** 343

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**Author:** ![KennyMoens](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/kennymoens/32/84061_2.png) [@KennyMoens](https://community.homey.app/u/KennyMoens)\
**Post date:** [July 29, 2026, 3:23pm UTC](https://community.homey.app/t/app-pro-viessmann-make-your-heating-smart/116744/343 "2026-07-29T15:23:06Z")

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Hey guys,

This is sadly something on viessmann side, we’ve seen it popping up in the past already a few times.

Some hints from this topic to try out:

> [@\[App\]\[Pro\] Viessmann App for Homey Pro](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/265):
>
> Hi I got it working again: Click on „repair“. Then you need to logon again. (you will see the same hint you can see in the vicare app). Restart the app This solved the issue for me.

> [@\[App\]\[Pro\] Viessmann App for Homey Pro](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/302):
>
> Hi Kenny, I get exaclty the same error as mentioned above, Invalid grant. It was working for months until the 1ste of december. I removed the client from the developers portal and created a new one. New ID used. then this error Error: Client authentication failed The other Viessmann app in the Homey store has the same problem. So probably something changed in the API

Let me know the results.

Kind regards

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