LumenRT Connect Edition - Why will the Bentley Account not sign in ?

Having an Issue with LumentRT v Update 5 and v Update 12 with on a single device. I install the package however when run the user is not logged in automatically and the sign in button in LumentRT is not active (does nothing when pressed). This happens when the user is logged into the Connection client and CC works fine with other Bentley products on the device. Bentley Account/CC working fine for same user on other devices. Any suggestions greatly received - Thanks