Right-click on Internet Explorer icon --> Properties.
Internet Properties window will be opened.
Click on Advanced tab.
Scroll down to the Security section.
Under the security section, uncheck the check boxes for Check for publisher's certificate revocation and Check for server certificate revocation.
Now look for the options Warn about certificate address mismatch & Warn if changing between secure and not secure mode and uncheck those options also.
Click on Apply button.
Now try to open that website. If the problem still exists then follow the next step.
2) If you find the option regarding the installation of certificates then install the certificates related to that site.
3) Third Step:
Add that website to Trusted Sites.
Right-click on the Internet Explorer icon --> Properties ---> Click on Security tab---> Select Trusted Sites --> Click on Sites button --> Add your website url in the text box (Example: http://www.example.com)
Click on Add button --> Uncheck the option Require server verification (https:) for all sites zones in this zone" and click on OK.
4) For more information regarding certificate errors, click on the this link