# \[App\]\[Pro\] Viessmann App for Homey Pro **URL:** \ **Category:** Apps\ **Tags:** app, homey-pro\ **Created:** [September 26, 2024, 12:33pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744 "2024-09-26T12:33:22Z")\ **Posts on this page:** 20\ **Page:** 17
**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:** [April 13, 2026, 1:36pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/326 "2026-04-13T13:36:03Z")
Hey @Thomas_Brenac The diagnostics report show me that the authentication against the Viessmann API has failed for an unknown reason. I’ve pushed v1.6.2 towards stable now, this version should give more feedback on the exact error. Kind regards, ---
**Author:** ![Thomas\_Brenac](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/thomas_brenac/32/121365_2.png) [@Thomas\_Brenac](https://community.homey.app/u/Thomas_Brenac)\ **Post date:** [April 13, 2026, 7:54pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/327 "2026-04-13T19:54:39Z")
Hi Thanks but same error (although the content is not written the same way, the message is the same) 164e5cc3-0315-46f5-8123-be1d535f2a60 ---
**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:** [April 14, 2026, 5:34am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/328 "2026-04-14T05:34:36Z")
Hello @Thomas_Brenac , This does not sound good. Did you exceed the threshold for the Viessmann API? Do you have maybe another integration with Home Assistant or something else? The error code you get is 402, which means “Payment Required”. Could you look in your Viessmann Developer Portal if you see any more information there? _PS: I have a feeling that Viessmann will start blocking these APIs in the future._ ---
**Author:** ![Thomas\_Brenac](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/thomas_brenac/32/121365_2.png) [@Thomas\_Brenac](https://community.homey.app/u/Thomas_Brenac)\ **Post date:** [April 14, 2026, 7:49am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/329 "2026-04-14T07:49:53Z")
Hi No other instance (I also use the official apps from vissman so maybe that is the reason it’s counting) and I tried apparently 31 times over several days. ---
**Author:** ![Thomas\_Brenac](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/thomas_brenac/32/121365_2.png) [@Thomas\_Brenac](https://community.homey.app/u/Thomas_Brenac)\ **Post date:** [April 14, 2026, 9:26am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/330 "2026-04-14T09:26:43Z")
hi each time i try to install the equipement via the apps it increases the counter in the developper dashboard. Now 35 in a month time all the rest seems ok and account is basic individual allowing 1450 api calls per day, and it is still indicated FREE 🙂 Shall i open a ticket with them ? what error code you see in return from them ? 7e97c017-2a85-4d9d-9531-f0f3c3114be0 kind regards ---
**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:** [April 14, 2026, 10:40am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/331 "2026-04-14T10:40:43Z")
Hey Thomas, The app gets HTTP error 402 during the OAuth2 handshake. Kind regards, ---
**Author:** ![Sebastian\_Richter1](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/sebastian_richter1/32/120718_2.png) [@Sebastian\_Richter1](https://community.homey.app/u/Sebastian_Richter1)\ **Post date:** [May 2, 2026, 5:13pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/332 "2026-05-02T17:13:12Z")
I created an ID, it worked too. However, I always get an error message when inserting the device. device or resource not found I have a Vitocal 222S ---
**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:** [May 5, 2026, 7:12am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/333 "2026-05-05T07:12:13Z")
Could you share a screenshot? ---
**Author:** ![zita](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/zita/32/10565_2.png) [@zita](https://community.homey.app/u/zita)\ **Post date:** [May 7, 2026, 7:26am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/334 "2026-05-07T07:26:35Z")
I went four weeks without Viessmann, wasn’t working, uninstalled the app yesterday, restarted Homey, reinstalled the app, and logged in. Everything is working again. Phew, thank goodness. ---
**Author:** ![JayR](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/jayr/32/123348_2.png) [@JayR](https://community.homey.app/u/JayR)\ **Post date:** [June 19, 2026, 9:16pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/335 "2026-06-19T21:16:15Z")
i was using the ViCare App but this app stopped working this morning, tried this one and the error is the same, so I assume a API error on my account. I always get a “premature closed” message from the server. What am I missing here? in the App Setting, the API Output calls: No OAuth2 Client Found. I’ve also deleted the apps, the token and everything was rebooted. Same issue. 230ede44-9133-4db0-8c86-441a2dad515b ---
**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:** [June 20, 2026, 5:34am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/336 "2026-06-20T05:34:15Z")
Hey @JayR The diagnostics report does not give me much info. Could you share more info on the error? E.g. some screenshots? Thanks, ---
**Author:** ![Joe75](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/joe75/32/19891_2.png) [@Joe75](https://community.homey.app/u/Joe75)\ **Post date:** [July 27, 2026, 5:54pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/337 "2026-07-27T17:54:24Z")
Hi Kenny, the API connection has stopped working today. I’ve already generated a new API key, but the error remains the same. The error is… failed to retrieve the features.json: [OAuth2Error] Error: Client authentication failed ---
**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 28, 2026, 8:57am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/338 "2026-07-28T08:57:54Z")
Hmm. Could you maybe share a diagnostics report? ---
**Author:** ![Joe75](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/joe75/32/19891_2.png) [@Joe75](https://community.homey.app/u/Joe75)\ **Post date:** [July 28, 2026, 10:50am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/339 "2026-07-28T10:50:23Z")
43fd7a9e-2b92-434e-9ee0-4962360171bd ---
**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, 1:27pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/340 "2026-07-29T13:27:08Z")
Hey Joe, I don’t get much wiser form the report, the authentication API from Viessmann tells me “Invalid grant” in your case. Did you try recreating the client completely? ---
**Author:** ![Geert\_Soeterboek](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/geert_soeterboek/32/67924_2.png) [@Geert\_Soeterboek](https://community.homey.app/u/Geert_Soeterboek)\ **Post date:** [July 29, 2026, 1:59pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/341 "2026-07-29T13:59:38Z")
Hi Kenny, Since 2 weeks or so I get the same “invalid grant” errror. I have removed the app completely and re-installed it. When adding a new device it wants to go to the login page of Viessmann, but that gives a “proxy error” page. So there seems to be going something wrong during authentication. Can you please help? ---
**Author:** ![Joe75](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/joe75/32/19891_2.png) [@Joe75](https://community.homey.app/u/Joe75)\ **Post date:** [July 29, 2026, 2:54pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/342 "2026-07-29T14:54:33Z")
Yes ---
**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-app-for-homey-pro/116744/343 "2026-07-29T15:23:06Z")
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 ---
**Author:** ![Joe75](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/joe75/32/19891_2.png) [@Joe75](https://community.homey.app/u/Joe75)\ **Post date:** [July 30, 2026, 4:16am UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/344 "2026-07-30T04:16:20Z")
Repair Helps ---
**Author:** ![Michiel\_Peters](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/michiel_peters/32/172872_2.png) [@Michiel\_Peters](https://community.homey.app/u/Michiel_Peters)\ **Post date:** [September 6, 2026, 9:00pm UTC](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744/345 "2026-09-06T21:00:41Z")
Hi Kenny, I think I may have found an issue with power consumption reporting for a Vitocal 200-S (AWB-M-E-AC 201.E10) in the Viessmann Homey app. The electrical consumption features are available when I query the Viessmann V2 API directly (`heating.power.consumption.current`, `.heating` and `.total`), including actual historical kWh values. However, these features are missing from the `features.json` generated by the Homey app, and consequently no `measure_power` / `meter_power` capabilities are created in Homey. I also have a Vitocal 150-A connected to the same Homey/Viessmann setup, for which the power reporting works correctly. I have the `features.json` and the direct API results available for comparison. I can’t seem to send you a PM yet. What would be the best way to send these files to you privately? Thanks, Michiel [Previous page](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744.md?page=16) [Next page](https://community.homey.app/t/app-pro-viessmann-app-for-homey-pro/116744.md?page=18)