Why I cannot activate my license?

[Moderator]

To activate your license you have to connect to license server over standard HTTP protocol.

If you have no access to license server, you will receive a following message:

No connection to license server.

Also there is a problem using JRE 6 updates 1 to 3. If you are using JRE 6 make sure you have at least update 4. It may be necessary to uninstall older updates.
If you have JRE 6 updates 1-3 or other unexpected error occurs, you will receive a following message:

Activation failure.

[Moderator]

Another possible problem with activation is proxy settings.

If you are using proxy you have to enable it in Eclipse. You have to enable HTTPS to activate license. To change proxy settings go to Windows > Preferences > General > Network Connections.