While trying to update the WP LinkedIn widget on a WordPress blog, I ran into an HTTP error I had never seen before: 414.
HTTP error 414 indicates that the URI is too long for the web server to interpret it.
In the case of a WordPress blog, this is likely caused by a security feature of the iThemes security plugin. If iThemes is being used, the first step would be to turn off the “Filter Long URL Strings” checkbox. This can be accessed through the WordPress admin console: Security –> Settings –> System Tweaks.
The checkbox is about halfway down the page.
I would suggest turning this off only long enough to complete whatever administrative action you are doing, and then turning it back on, so as not to create an unnecessary vulnerability.
If you are not running iThemes, the setting is likely found in the Apache configuration, and may need to be addressed there.