I keep getting an error saying: "An error occured. Network request failed" on the app and on the actual website I can't email past courses.
It depends a little on how your school has Canvas set up. There is a setting which might be enabled that "concludes" course after the end date of the course or semester. That essentially makes the course read only and prevents any changes being made to the course, and also limits the ability for people to communicate with each other through the course. It sounds like this might be the case at your school.
I suggest checking the Syllabus in the course to see if your teacher has their direct email listed and trying emailing them instead of sending a message through Canvas.
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