@isaac cordova
That is probably not the reason, because they could be under the same user id in DocuSign, so it is actually just one user account and there is one security section. If they are external accounts they will not have your federated ID in them as they are not connected to your environment it was never passed to those accounts.
It could be the case that she was logged into DocuSign with on of the old accounts when she tried to authenticate in Salesforce. In this case it would have tried to use the already logged in user credentials. You can ask her to login into her DocuSign account via SSO and ensure it is the correct one. After then authenticate with Salesforce, which should use the logged in user to authenticate, which should work.
The email address needs to be exactly the same in DocuSign and in Salesforce. In case you have different domains and used different ones for both systems. This could be another reason that it is not working.