This issue I have already solved
We enter / modules / mod_sj_minicart_pro / and open the file mod_sj_minicart_pro.php with the text editor.
Now we look for line 45 and change http that appears at the end of the line by https
$ cart-> ajaxurl = strtolower (substr ($ _ SERVER ["SERVER_PROTOCOL"], 0, 5)) == 'https: //'? 'https: //': 'http: //';
The line should look like this ..
$ cart-> ajaxurl = strtolower (substr ($ _ SERVER ["SERVER_PROTOCOL"], 0, 5)) == 'https: //'? 'https: //': 'https: //';
regards