Firefox will not open web pages from bookmarks

I’d first check whether it’s the profile rather than the bookmarks themselves. Try opening a bookmark in Troubleshoot Mode. If they work there, an extension or setting in the original profile is probably interfering. If they still don’t open,''' right-click one of the bookmarks → Properties and check the URL.''' You can also try copying the URL and pasting it directly into the address bar. If the pasted URL works, the bookmark database may be the problem. Since you said the original profile is the one affected, I’d avoid deleting or creating a new profile until you’ve backed up the bookmarks.