A certificate error message in Internet Explorer is designed to pop up when the browser detects a website's security certificate contains invalid information. This is done to protect Web surfers from malicious websites that can download viruses or fake websites set up to gather personal information. But sometimes this security feature goes awry and begins to block trusted sites the user knows are safe.
Close Internet Explorer, then click the "Start" button. Type "regedit" in the search box if you are running Vista or in the run box if you are running older versions of Windows. Hit "Enter."
Highlight "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\Main\FeatureControl" by clicking on it.
Highlight "New" in the edit menu and click "Key."
Type "FEATURE_ERROR_PAGE_BYPASS_ZONE_CHECK_FOR_HTTPS_KB954312" in the new key box and hit "Enter."
Highlight "New" in the edit menu and choose "DWORD Value."
Type "iexplore.exe" in the value box and hit "Enter."
Choose "Modify" in the edit menu and enter "1" in the modification area. Click "OK."
Close the registry editor and open Internet Explorer to see if the certificate error problem is fixed.
Before you attempt to fix the problem through a registry repair, check to make sure the date and time on your computer is correct. Often, something as simple as adjusting your clock settings can fix an invalid certificate error. Also check your security settings. Sometimes security software will block a webpage for no apparent reason. If you trust the website, adjust your software to allow IE to display the page.