The problem is that a Windows security prompt is being invoked but does not appear through the TaxAct program interface. This prompt appears in Internet Explorer because Microsoft also uses that for system wide settings related to Internet connection.

Please try this:

1. Open Internet Options, from Internet Explorer (Tools menu or gear icon) or the Control Panel. You can type "Internet Options" in the Windows search bar on the Start menu.
2. Go to the Advanced tab.
3. In the Settings area, scroll all the way to the bottom. The bottom section is Security.
4. UNcheck the box next to "Warn if changing between secure and not secure mode" (it's usually the second to last item in the settings).
5. Click the Apply button in the lower right.
6. Click OK to exit the Internet Options dialog box.