Forge - Problem with Deploy Key

Hey everybody,

took over a Forge Account and now trying to set it up with another Github Account.

When trying to install a Repository I get an Error (We were unable to install a project on your server ). I then (like suggested) tried to add a Deploy Key to my Repo in GitHub, but get the messasge ("Key is already in use"). What is happening? Is the Deploy Key still linked with the other Github Repo (don't have access) SSHed into Forge, but could not find a solution...

Appreciate any help!

Kind Regards Casimir