There is a few things that you can review:
- Ensure that you have billing setup.
- Make sure you don't run any firewall/anti-virus/vpn/filtering service on your pc or network.
- Try to do it from a different PC and from a different network without any extension running
This could a temporary delay or something is blocking it from enabling. Can you also provide us with a screenshot(s) of the error and from where you're trying to enable it and do you get the same thing if you try to enable any other services?