Hello @KaylaBrimlow
While I haven't seen that specific error, I have seen others like that and it is usually due to duplicate assignment titles or assignment groups. Double check and make sure there aren't any duplicates in the gradebook or assignments tab. There is a good likelihood that this is the issue.
If you have more questions regarding this issue(s) please feel free to respond with descriptive information as to give us a clear insight into the problem.
You are also welcome to reach out to Canvas Support directly, to pinpoint the source of the issue and provide a resolution:
How do I contact Canvas Support? - Instructure Community
Here's a list of common SIS errors:
SIS Error Code Dictionary - Instructure Community