Why is Figma Prototype distorted when it is shared?

I had a project for an online course I am taking. I did all my work using the Figma desktop app. When I reviewed the prototype it looked fine. I shared it with a classmate and he said it was distorted and sent me a screenshot. He said others in the class have the same problem. When I opened the Figma file in a browser it was not ok it was also distorted. Is there something wrong with the Figma desktop app? Should I only use Figma through a browser? Which browser? Thanks