Weheat will not install

Hi I am new to Home Assistant, i bought the HA green and after some trial and error I managed to add my home wizzard, my HUE lights and my sunpanels.
But now I got stuck on installing the weheat ingegration, maybe because there is some caching issue ?
I try to add the weheat integration and added the oAuth API and the secret key I found at weheat and on HA
Then the login screen from weheat should appear but I got an Error with: client not found
How can I solve this (my weheat green is only available on my local network)

Hi, can you provide some screenshots of the issue? That will help people see what exactly the issue is.

Solved this issue with a litle help from my son.
The Oauth API and Secret code is entered was possible wrong (typo) and HA stores this info before it is connecting the Weheat site where you need to enter the Username/Password from your Weheat user account.
So with another attempt HA uses this wrong info.
How to solve it: Got to Settings>Devices & Services, click the tree dots and you see the Application credentials and at the end of the line (rigth) when you click on the 3 dots you can remove them.
Now I can add the integration again and can fill in the right API name and secret key and then it goes to the weheat and the error (client not found) is gone and I can loggin and the integration was succesfull

BTW, The last step: Weheat wants to connect to HA and sends an URL with port 8132 filled in, but at newer HA installations this is changed to the standard port 80, but you can change this url before clicking on it
So issue solved.