1. Open Windows Firewall (Start -> Control Panel)
2. Double click on Windows Firewall icon

3. Ensure the check box "Don't allow exceptions" is unchecked.

4. Open the "Exceptions" tab.
5. Click on the "Add Program." button below the list of Programs and Services.

6. Select Vedivi from the list and click OK.

Well done, your Firewall is now configured for Vedivi to connect properly to the remote computer.
Restart Vedivi and try again to sign in to Vedivi.

You might still have to authorize the whole remote network (or some computer selectively). But normally, it should be enough (for a default configuration).