A cloud-based identity and access management service for securing user authentication and resource access
If it's working in Chrome then there probably isn't anything wrong with the setup itself. Things to try:
- Update to the latest Firefox browser if you have not already done this.
- Check to see if the issue persists if you clear the cache.
- Check to see if the issue occurs if you use an in-private window.
- In Firefox go to Settings > privacy > remove individual cookies
Search for Outlook and delete everything. Then search for office delete again. Or, if you don't care about logins for everything, remove all cookies. (This isn't a convenient solution but may be necessary if there's a caching problem.)