Language Cloud engine not found

Hello, Could anyone help me solving my problem: I use SDL Trados Studio 2017 SR1 and before it was OK, since two weeks I did not use it. Now, when I try to open a new project, I constantly get the message : ''An error has occurred while using the translation provider SDL Language Cloud Machine Translation: Language Cloud engine not found''

I restarted Studio many times but no results.

Your help is highly appreciated !!