Just wanted to share some information about an issue that took us a long time to resolve as this did only happen with Safari browsers and we were not able to reproduce it consistently. When using the Office Add-in Business Inbox in the Safari browser, there is a continuous loop of authentication attempts. This is because Safari blocks third party cookies by default.
More information here:
https://www.clubrunnersupport.com/article/710-enable-third-party-cookies-for-safari
https://www.engadget.com/2020-03-24-safari-blocks-all-third-party-cookies-by-default.html
if you do run into this scenario, you now know what to do.
Thanks.
Not a question but feel free to respond if things are not clear.