Can't open Word files on Mac OS Monterey 12.7.6 via Office 365 - denied permission of my own docs

I am running into problems with trying to open my own files. Files I open in Word from Box. Word docs some people send to me. I click on Grant Access and am told I don't have permission to open them. I have a 2015 Macbook so I can't upgrade to Sequoia. I wonder if something changed at Office 365. I really need to open these docs.