The problem is an DNS issue with MTN, their technicians are attending to the problem. In the meantime browsing is impossible. The quickest solution to fix this is to not use the MTN DNS but another DNS (domain name system).
One that you can use is Google’s free Public DNS. What you want to do is access your router and change the DNS settings. Your router by default will use your ISP’s DNS settings, change that to use Google’s free Public Domain Name System. The process is relatively simple but will obviously vary depending on your particular router.
If you are comfortable with changing your router settings it will take less than a minute, if not contacting your ISP or asking someone you know will be the way to go.
The Google free Public DNS settings are:
Use 18.104.22.168 and 22.214.171.124 as your DNS servers.
For more info read this: https://developers.google.com/speed/public-dns/
And voila! Once I changed my settings to use the Google Public DNS my browsing was immediately restored.