If a Windows user account tries to install updates through the CONNECTION Client and that user does not have the administrator rights to install, then the installation may fail, and time out after admin credentials are entered in the prompted credentials windows, or may succeed, but will cause signing in errors after the installation.
CONNECTION Client update needs to be performed on the local Windows administrator account, not by providing the administrator's credentials on a non-Administrator account.
Sign in as the Administrator user account and install the CONNECTION Client update.
Installation - Manual
FAQ - CONNECTION Client