Updated WP Polls plug-in created system error

Disable that plugin — rename the directory wp-content/plugins/wp-pollsto wp-content/plugins/wp-polls.old using FTP or your hosting control panel. That will get your site back.

Then report the problem here: https://ww.wp.xz.cn/support/plugin/wp-polls

You can grab the prior version here: https://ww.wp.xz.cn/plugins/wp-polls/advanced/ and replace the one currently on your site or wait for an update.