@yeelinda I apologize that no one has responded to your question before now.
The students don't necessarily have to make their eportolios public, but if they do, anyone with the URL can view them: How do I make my ePortfolio public as a student?
Making visibility public might be an issue, and in that case students can follow the instructions in How can I share a private ePortfolio as a student? to obtain the correct link to share a private eportfolio with others.
If these processes aren't allowing unauthenticated users to view students' shared eportfolios, please ask Canvas Support to investigate on their behalf.
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.