RE/Xplorer requires that *.rexplorer.net be defined in Internet Explorer's trusted sites zone.

To add *.rexplorer.net to Internet Explorer's trusted sites zone.
1. Click on Tools in the menu bar.
2. Click on Internet Options in the drop down list.
3. Click on the Security tab.
4. Click on the Trusted Sites icon.
5. Click the Sites button.
6. Enter *.rexplorer.net in the input area below the text that reads "Add this Web site to the zone".
7. Verify that the box to "Require server verification (https) for all sites in this zone" is NOT checked.
8. Click on the Add button.
9. Click the OK button.
10. Verify that the security level for the Trusted Sites Zone is set to the default (low).
11. If you changed the security level click on the Apply button.
12. Click the OK button.
13. Click the Refresh button.