While Internet Explorer and Chrome use the certificates installed on your computer. FireFox requires manual install of certificates in it.

NOTE: Chrome is the MWISD preferred supported browser. Internet Explorer is also supported but not preferred.

Source:  https://support.cipafilter.com/index.php?/Knowledgebase/Article/View/42/9

This network employs a technology called SSL filtering which allows your network's administrators to filter out harmful or inappropriate Web content such as viruses and pornography. In order for this technology to work effectively, the network's filtering unit must issue to your computer or mobile device a file called an SSL certificate.

This guide will help you install the SSL filtering certificate for browsers based on the Mozilla platform, such as Firefox.

Step 1

Visit your domain's portal page to download a certificate. By default, this is https://portal.cipafilter.com.  First, click the Download Certificate button; this will begin a download of the file to your computer.
 

Step 2

Firefox CA trust prompt
 
Next, a dialogue will appear indicating that you have been asked to trust a new Certificate Authority. In this window, make sure that Trust this CA to identify web sites is ticked, and then click OK.
(Note: This image shows Firefox on Mac OS X. If your computer runs Windows or Linux, the buttons may look different — but the words should be the same.)

Step 3

You're done! You may continue browsing as usual; in most cases, you will not notice anything different after the certificate is installed.