A required anti-forgery token was not supplied or was invalid
After adding the AntiForgeryToken to prevent Cross Site Request Forgery, I started getting the following message when I was debugging the site
“A required anti-forgery token was not supplied or was invalid.”
With the following inner exception
Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.
After Googling around for a bit and trying many other options, a much simpler and quick solution rose, clearing the cookies. There are some fixes and additional info about the issue, but this is a quick fix/hack for somebody who needs to move past quickly.
Hopefully you didn’t spend too much time Googling. I get this quite a bit from site to site, it’s amazing the goodness that can come from clearing cache, cookies, etc…