"OneDrive authentication failed"

@Sophia Tabor - That message looks to be Microsoft telling you that the admin of your Microsoft/OneDrive account that your email address (*6@s*.whatever) needs to approve the connecting of the “Miro (formerly RealtimeBoard)” to your OneDrive.

You will need to reach out to whomever administers your email/Microsoft account. You mentioned you are a student, so this is likely someone in your educational institution’s IT department.

In the mean time, I would just suggest that you link to any of your OneDrive files using a regular link, just like you would when adding any link to a Miro board. You can read more about this in Internal and External Linking Help Center article.