Error 15 indicates that you were not able to communicate with the license server.
In a situation such as that, a typical way to get around the problem would be to establish a VPN (Virtual Private Network) back to campus.
If you had been using a Professional / Commercial license then potentially your server could have been configured ahead of time to allow you to "borrow" a license; https://www.mathworks.com/help/install/license/borrow-licenses.html . However, that is not available for academic licenses.
