Sorry, but it doesn't work for me at all. When I try to add a service, I get the login screen for few seconds, and then the whole window turns gray and I can't

Sorry, but it doesn't work for me at all. When I try to add a service, I get the login screen for few seconds, and then the whole window turns gray and I can't type anything, the only thing I can do is to close it. Tried several times with different services. Tried macOS version on High Sierra.