The common reason which causes such this problem to happen is your site’s permalink structure can’t be automatically rewritten after updating. The easiest way to fix is to flush your permalink by visiting Settings > Permalinks in your site dashboard. And then just hit the save button. If it fails, try to enable plain permalink option. If doesn’t give any change, you’d need consult to your hosting support department, as there might be server configuration issue.
ok, thx! working now!
Please let us know in a new topic if you have any further questions, or if we can provide you with any other assistance.