Magento 2.3.5: Showing Invalid Form key on every page

Question

We are facing an issue after upgrading Magento version to 2.3.5.

Invalid form key. Please refresh the page.  

is showing on every page only on safari browser.

Answer 1

Ok I fixed this error by updating my cps_whitelist.xml file.

Unfortunately I can't say what policy fixed it. I think it was in policy id="connect-src" for Facebook.com

https://sherocommerce.com/magento-content-security-policy/

We are having the same issue after upgrading to Magento ver. 2.3.5-p1 Only affecting safari browser. I've changed to developer mode with bin/magento d:m:set developer Ran rm -rf var/di/* var/generation/* var/cache/* var/log/* var/page_cache/* var/session/* var/view_preprocessed/* And then bin/magento d:m:set production to recompile and clear caches Issue still present in safari only.

Answer 2

Try a clear browser cache and delete the cookies.

Check the Magento error log file if logged with any error.

If not work then please try to increase the value of max_input_vars in the php.ini file. By default, this value is set to 1000. You should set it to 5000 or 10000.

Also, check by removing generated, var/cache, var/page_cache, var/view_processed directories, and run below commands in case if it helps to solve the issue.

php bin/magento setup:di:compile
php bin/magento cache:clean
php bin/magento cache:flush