Thank you for the additional information, @Carefree_creation6eb0.
I'd like to understand better the environment in which Creative Cloud is used.
Is this laptop or desktop provided or managed by your school, or are you connected to your school's network when the error occurs?
Error 12015 can occur when device or network policies managed by an organization interfere with Adobe licensing services. If your school manages the computer or network, its IT department may need to grant access to the Adobe licensing services required for your individual subscription to function properly.
If this is your personal device on a home network, please let us know, and we'll continue investigating other possible causes.
Please let us know whether your school manages the device or network, and we'll be happy to help further, @Carefree_creation6eb0.