The most recent request was denied because it had an invalid security token
The answer to this question was found here:
Better Preview does not work well with the "Shared Sessions" setting on in the Global Configuration.
I advise you to switch that off.
Let's continue the discussion here.
When i add from backend it work but not on frontend.
I also tried to vote on an item (add from backend) but i get invalid token message.
I cannot reproduce this issue because of no enough permission to submit an entry on the front-end.
CSRF token is not the problem caused by NorrCompetition, some 3rd party extension does it.
I see you have Admin Tools. Try disabling it to make sure the problem is in it.
I recommend disabling Admin Tools first to make sure the problem is caused by this extension and then you need to configure Admin Tools settings. Go to Web Application Firewall and examine settings there.
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