Connecting to a Boot2Qt device requires a git installation for ssh and sftp on Windows.

It was not possible to connect to a device until we installed git.

Providing the tools in a different folder did not seem to work.

Qt Creator was always looking for ssh in 'C:\Program Files\Git\usr\bin\ssh.exe'.
Browsing the folder in the settings and setting another path to an existing ssh.exe did not work. Qt Creator seemed to always look for ssh.exe in the default path.

Installing git including ssh did solve the issue.