If you're getting an error message that the Redgate Client Service won't start, a firewall rule may be preventing local use of HTTP. Please open an administrative command prompt and try the following commands:
This first command shows if any rules are defined.
>netsh http show iplisten
If there are no rules, then by default all services are white-listed. However, if the default is changed or if there is at least one rule then it may be necessary to add an extra one.
>netsh http add iplisten 127.0.0.1
Once added, please navigate to http://localhost:22221/redgate/status.html again to activate the license.
If this doesn't help, or if other non-RG services are affected then please raise a support ticket. The rule can be removed.
>netsh http delete iplisten 127.0.0.1