About two weeks ago facebook has blocked me from tagging anyone on anything (ie: using @) on mobile. I am an Android user.
I can tag on desktop.
I have tried clearing my cache, cookies etc etc.
Can't do it on both browser and app.
Does anyone know what might be wrong?
What makes you think Facebook blocked you from tagging anyone? If they've blocked you, then I don't think you'd be able to tag on a desktop either.
Try uninstall and reinstall app.