Share via

Office Add-in development: Can't sideload add-in in VSC; it returns 401 unauthorized despite having a 365 developer E5 subscription

Marcos Mayer 0 Reputation points
2025-04-07T16:14:51.8166667+00:00

In short, I am trying to do this tutorial in Visual Studio Code: https://learn.microsoft.com/en-us/training/modules/office-add-ins-outlook/

However, when asked to start the add-in, it throws an error and says "401 unauthorized". Searching about it I found that it's because personal accounts cannot sideload manifests, but I have a 365 developer E5 subscription, so it should allow me to run my add-in.

How can I fix this?

Thanks in advance

Office Development
Office Development
Office: A suite of Microsoft productivity software that supports common business tasks, including word processing, email, presentations, and data management and analysis.Development: The process of researching, productizing, and refining new or existing technologies.
4,345 questions

Your answer

Answers can be marked as Accepted Answers by the question author, which helps users to know the answer solved the author's problem.