Magento admin login Error : invalid form key. please refresh the page

Question

I am new to magento. I have recently setup my site on magento. Today I was trying to increase the logout time frame for admin session as it used to logout in few seconds. As I tried to save the time to 600 seconds. I received an error on the page. and since then I am not able to log into my magento admin login though the site is working fine.

when ever I try to login into my admin. I receive an error stating

"Invalid form Key. Please refresh the page."

I have tried finding the solution and tried a solution form a below page to add "return true" in "Session.php" page.

https://github.com/nexcess/magento-turpentine/issues/1077

Though, not of much use as after using this solution only the error message got disappeared but I am still not able to login.

We are using Magento 1.9.2 version

• David Verholen: since youre posting a turpentine issue here, did you try to get in after deactivating the varnish? Varnish can be really nasty if it, in your example, maybe caches the form-key? Or maybe just access the site over the backend port you configured, to bypass the varnish? Although the turpentine config does, as far as I know, ignore the magento backend it might be an issue in your case that backend login page is cached

Answer 1

Such issues comes due to cookies or cache problem. Delete cache from your magento_root/var/cache and remove cookies from your browser. One more reason may be incorrect data in web/cookie/cookie_domain and web/cookie/cookie_path values in core_config_data table.