How to fix «Unable to send the cookie. Maximum number of cookies would be exceeded»

dmitry_fedyuk · September 25, 2015, 3:12pm

Magento 2 throws an exception if your browser session already have 20 cookies set and Magento need set some additional cookies:

Unable to send the cookie. Maximum number of cookies would be exceeded.

See the code:

github.com

magento/magento2/blob/daf301d625d8652996a6d3c9400e5f9816184bde/lib/internal/Magento/Framework/Stdlib/Cookie/PhpCookieManager.php#L182-L186


      
          if ($numCookies > PhpCookieManager::MAX_NUM_COOKIES) {
              throw new CookieSizeLimitReachedException(
                  new Phrase('Unable to send the cookie. Maximum number of cookies would be exceeded.')
              );
          }

github.com

magento/magento2/blob/daf301d625d8652996a6d3c9400e5f9816184bde/lib/internal/Magento/Framework/Stdlib/Cookie/PhpCookieManager.php#L27


      
          * sensitive data so that extra protection can be added to the contents of the cookie as well as how the browser
          * stores the cookie.
          */
          class PhpCookieManager implements CookieManagerInterface
          {
             /**#@+
              * Constants for Cookie manager.
              * RFC 2109 - Page 15
              * http://www.ietf.org/rfc/rfc2109.txt
              */
             const MAX_NUM_COOKIES = 20;
             const MAX_COOKIE_SIZE = 4096;
             const EXPIRE_NOW_TIME = 1;
             const EXPIRE_AT_END_OF_SESSION_TIME = 0;
             /**#@-*/
          
             /**#@+
              * Constant for metadata array key
              */
             const KEY_EXPIRE_TIME = 'expiry';
             /**#@-*/

I think this is the issue: Magento need handle the situation in some other way, not throwing an exception.
The issue is documented in Magento 2 issue tracker (#1500) and I expect it will be fixed to the Magento 2 Merchant Release date.

But now you need to clean some old cookies manually.
Here is an instructon for Google Chrome browser:

Open Developer Panel by pressing F12 key

Select the Resources tab at the top of the Developer Panel.
Select the Cookies tab at the left of the Developer Panel.
Navigate to your store’s domain subitem of Cookies item:
Delete (by pressing DEL key) some cookies not related to Magento 2.
At the picture below I clean WooCommerce cookies:

dmitry_fedyuk · November 17, 2015, 4:52am

Looks like Magento 2 uses an obsoleted specification RFC 2109 for cookies limit.
The new specification is RFC 6265, and it allows at least 50 cookies per domain.

So the MAX_NUM_COOKIES limit can be safely increased up to 50.

Locate the line:

github.com

magento/magento2/blob/daf301d625d8652996a6d3c9400e5f9816184bde/lib/internal/Magento/Framework/Stdlib/Cookie/PhpCookieManager.php#L27


* sensitive data so that extra protection can be added to the contents of the cookie as well as how the browser
* stores the cookie.
*/
class PhpCookieManager implements CookieManagerInterface
{
   /**#@+
    * Constants for Cookie manager.
    * RFC 2109 - Page 15
    * http://www.ietf.org/rfc/rfc2109.txt
    */
   const MAX_NUM_COOKIES = 20;
   const MAX_COOKIE_SIZE = 4096;
   const EXPIRE_NOW_TIME = 1;
   const EXPIRE_AT_END_OF_SESSION_TIME = 0;
   /**#@-*/


   /**#@+
    * Constant for metadata array key
    */
   const KEY_EXPIRE_TIME = 'expiry';
   /**#@-*/

Replace it with the new one:

const MAX_NUM_COOKIES = 50;

See https://github.com/magento/magento2/issues/1500#issuecomment-156421883

dmitry_fedyuk · November 17, 2015, 5:07am

See the cookie limits for the modern browsers.

dmitry_fedyuk · November 18, 2015, 10:53am

It is fixed in the current release: https://github.com/magento/magento2/blob/2.0.0/lib/internal/Magento/Framework/Stdlib/Cookie/PhpCookieManager.php#L29