Why Is Canva Blocked?
Canva doesn't block any region. You can access the design tool from anywhere in the world without any restrictions and you can design on the free plan whatever you can imagine - or, you know, just use a template like the rest of us.
Why Is Canva Blocked?
If you are unable to access Canva it's probably something on your end or your ISP (internet service provider) is blocking access to the tool.
Or someone from your school or institution is blocking access to Canva.
But before you panic, maybe see if a browser extension like Adblock is giving false positives and blocking the domain. Or any other plugins that gives false positives.
Lastly, you could always try to restart your computer or device. Maybe that will fix your problem.
If it doesn't you can always send them an email and explain your problem: support@canva(dot)com
I'm sure they will be glad to assist and help you fix your problem.