It's a Little "tricky" how MainWP is describing this requeriment, what they really means is not cURL specific, they are asking for incresing a PHP parameter that affects every socket connection (not only cURL).
Go to your php.ini file: /etc/php/7.3/fpm/php.ini and change the default_socket_timeout parameter. Don't forget restart the PHP service to changes takes effect: sudo service php*-fpm reload.
If you are doing it very often you can use the Webinoly Internal-API feature to automate this task.
To be honest, I don't think this will be integrated to Webinoly any time soon, I'm a little reluctant to use tools or plugins that need this kind of custom configurations, sometimes this things can have serious side-effects.
I was glad to see (read) you here.
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