That may be as expected. Many school accounts do not have access to Lightroom Desktop. If your school has not purchased "Services" or allocated Cloud Storage to your particular ID, Lightroom will not allow you to add photos. Since the application is, among other things, a cloud storage portal, if you do not have cloud storage provisioned on your account, you can't add photos. You would need to speak to your school's license administrator or use Lightroom Classic instead.