The warning you are seeing is because a secure site also has some non-secure content which can represent an insecurity (although often isn't a threat) so the browser warns you. This is what they consider the "Prompt" option.
To eliminate that from warning you each time, you need to edit the security settings in your browser, with the following steps:
To allow mixed content
- In Internet Explorer, click the Tools button, and then click Internet Options.
- Click the Security tab, and then click the Custom Level button.
- In the Security Settings dialog box, scroll to the Display mixed content setting in the Miscellaneous section, and then click Enable. Normally this will be at Prompt.
- Click OK in the Security Settings dialog box, and then click OK to exit Internet Options.
That's it! You won't see the warnings again.