error log

Hello,

I install ajax search pro an a wordpress multisite.
The search on the main site is set to search the subsite of the network.
Everything is working well but i have this error in the logs:

2020/04/28 08:37:26 [error] 2146#2146: *350 FastCGI sent in stderr: “PHP message: PHP Warning: count(): Parameter must be an array or an object that implements Countable in /www/mywebsite/public/wp-content/plugins/ajax-search-pro/includes/classes/search/class-asp-search.php on line 204” while reading response header from upstream, client: 80.214.122.203, server: mywebsite, request: “POST /wp-admin/admin-ajax.php HTTP/1.0”, upstream: “fastcgi://unix:/var/run/php7.4-fpm-thedownloadcenter.sock:”, host: “www.mywebsite”, referrer: “https://www.mywebsite/”

I have got this error each time i enter text on the search bar and the result show, i do not have to click on the result to get the error.
I have also search form on other subsite of the network, searching trough post. I have no problem, no error log. they have the same theme and plugin.
It look like the only difference is what they are search for (post or subsite).

Do you need login?

Thank you for your help.