Hi Chris,
According the office.js team if you are using forMSGraphAccess: true
as the parameter for getaccesstoken() then you are expected to see the 13102 error.
This is due to you have side loaded the addin, if you are using forMSGraphAccess: true you need to deploy the add-in via the admin center.
Please go through the git issue i raised: https://github.com/OfficeDev/office-js/issues/2711
You can set forMSGraphAccess: false and call the getaccesstoken() and you will no longer see the 13102 error. The good thing is that you can still use the token to make Graph API Call. I hope this helps you.