Word docs not opening in browser

This has been happening for a week or two in Firefox, and now occasionally in Chrome: Word docs often (but not always) will not open in the browser. Not a huge problem when opening from the Documents library, where you can choose to open in App, but we have linked to docs from other locations, and if they don't open from the link, staff has no idea where to find them. Message attached. Anyone else this is happening to? Help?