When attempting to load an embedded Excel file using Firefox or Chrome in Jira cards, we are prompted to sign into Office 365. Upon doing so, a window momentarily pops up that displays a green check mark (implying that log on was successful), however the sign in prompt remains.
This issue does not occur when using Edge, so that will work as a bandage, but most users here are deeply invested in Firefox or Chrome, so a solution for those browsers would be greatly appreciated.
Thanks in advance for any possible advice!
Kinda stumbled on the answer myself, and even though it feels a bit obvious in retrospect, I figured I would drop it here in case anyone winds up having the same day I did.
Firefox and Chrome seem to have more strict default cookie security settings than Edge (hence why the issue did not occur in Edge). The problem browsers were blocking cross site cookies for Microsoft Sharepoint. Creating an exception for cookies from Sharepoint.com resolved the issue.
Thanks to all who took the time to read my almost information-less post and make sense of the issue!