Hello @ArabellaEagar ...
I am sorry to read that you are having difficulties with some links in your course. We don't have access to your school's Canvas environment or any of the courses you are taking there, so we won't be able to help directly. You did say that you don't have an instructor for this course because you are taking it independently. In that case, I would suggest that you reach out to your school's Online Learning / eLearning / Distance Education team or their Canvas administrator(s). Someone should be able to help you get things straightened out. Typically, if an instructor is assigned to the course, the instructor has an option in the course to check for broken links. It almost sounds like this is what is happening in this course, and it's nothing on your end you'd be able to correct on your own (unless you knew of the exact URL to view). The link validation tool that the instructor has access to scans the entire course looking for broken links and external website links that might be unresponsive and may need to be checked to ensure they work for all students.
If you are able to get in contact with someone from your school, you can give them this link and ask them to verify links in that course: How do I validate links in a course?
I hope this will be helpful for you and the people you are able to talk with at your school. Good luck!