In Tools → Add-ons, are the integration plugins listed and enabled?
If not, if you close Zotero, go to your Zotero profile directory, and move extensions.ini, extensions.json, and the 'extensions' folder to your desktop, and then restart Zotero, does it work? (If any of those don't exist, that's OK.)
If not, if you close Zotero, go to your Zotero profile directory, and move extensions.ini, extensions.json, and the 'extensions' folder to your desktop, and then restart Zotero, does it work? (If any of those don't exist, that's OK.)