I am logging this here to have as a reference when students report issues with inability to upload or embed documents in Canvas. This is typically due to their having run out of space.
To check if this is the issue, the student would need to do the following:
Log into Canvas, go to Account, then select Files
Scroll down and check if the % used of storage is close to or exceeding 100%.
Should the student need to clear space, they could do so from previous courses by clicking the 3 dots, and then selecting delete.