Go to your hosting and delete all files in the directory of cformsii plugin
/wp-content/plugins/cformsii
Download the cformsii version 14.9.5 available in the wordpress page (https://wordpress.org/plugins/cforms2/) to your local computer
Upload this old version (14.9.5) to your hosting in /wp-content/plugins/
Extract the gzip file into /wp-content/plugins/
Go to your wordpress admin and active the plugin if necessary
It is done.
I have the same problem. After change to the version 14.9.5 there is no problem.
