Can't Edit with Word Online

I am trying to collaborate on a word doc using Word Online. My co-worker is currently on the document, but I do not have the option to open with Word Online; the only options are to open in Word or Google Docs:

I tried going to "integrations" under account settings, but Microsoft Office Online is grayed out and I cannot select it as an option. 


I've already tried the solutions shared in this similar thread: https://support.box.com/hc/en-us/community/posts/7162646179475-No-option-to-edit-Word-document-online
Also, this is happening in all of my Box files; it is not specific to one file or folder.

Any thoughts about what is happening or how to fix it?