For development on local machine make sure you:
- Setted up certificates https://github.com/OfficeDev/generator-office/blob/master/src/docs/ssl.md
- Side-loaded add-in in excel https://github.com/OfficeDev/office-js-docs-pr/blob/master/docs/testing/create-a-network-shared-folder-catalog-for-task-pane-and-content-add-ins.md