Sorry that Lightroom Desktop won't allow you to add photos and shows the imported images as grayed out.
Which version of Lightroom Desktop are you using and what is your computer's operating system?
Would you mind signing out of the Lightroom app and then sign back in? If that does not help, please try resetting the Lightroom app preferences to default? Press and hold the Shift + Option + Delete keys.(Mac) or Press and hold the Shift + Alt keys while starting Lightroom. A dialog box should appear asking you restore the preferences.