I have this error at update today to version 1.7.1. I dont remember my previous version, but it work great.
I get this error on my testing site:
Warning: count(): Parameter must be an array or an object that implements Countable in /home/user/mysite.com/wp-content/plugins/data-tables-generator-by-supsystic/vendor/Twig/Extension/Core.php on line 1275
After these operations are maid and the issue still persists,
most likely there is a conflict with your other plugin or your theme. We hope you understand that we can’t test our products with all other plugins and themes that are available on the market, and we can’t control the other developers. Therefore bad code of other plugins or templates can provoke a lot of problems.
Please try to deactivate all your plugins one by one and check the issue. Thus you will find out which plugin causes the error. If it won’t help, try to switch temporarily to a standard WordPress theme.
Then, let us know about the result. This will help our developers to solve your problem faster.