I can't update from mojave to catalina
I have a 2019 macbook pro, which is currently running mojave 10.14.
I loaded all its contents from time machine from my old laptop.
However, when I try to update from mojave to catalina, i either get a thing saying that there are no updates available, or that my laptop is 'unable to check for updates - make sure to connect to the internet' even though my laptop is connected to the internet.
Is there anything I can do to fix this?
MacBook Pro 13”, macOS 10.14