PHP warnings

Hi,
the plugin, at the bottom of the edited page, throws two following warnings:

Warning: Use of undefined constant CURLOPT_RESOLVE - assumed 'CURLOPT_RESOLVE' (this will throw an Error in a future version of PHP) in /wp-content/plugins/wp-to-buffer/vendor/includes/admin/api.php on line 142
Warning: curl_setopt_array(): Array keys must be CURLOPT constants or equivalent integer values in /wp-content/plugins/wp-to-buffer/vendor/includes/admin/api.php on line 142

Here is my hosting’s PHP configuration info.php73
WordPress 5.2.4
Post to Social Media – WordPress to Buffer 3.5.4
Screenshot with the Warnings