office 365 sign in problem

I am using Safari 10.1.2 on macOS Sierra 10.12.6. My company recently switched to Microsoft Office 365 and requires me to use Office 365 (https://login.microsoftonline.com). When I attempt to do this in Safari, I get

Sorry, but we’re having trouble signing you in.

We received a bad request.

I have successfully signed in using both Firefox and Google Chrome browsers.

I would prefer not to have to switch browsers to sign in to my company's Outlook Web Access.