Hello Anna

The number of rows certainly is high. wpDataTables that are linked to external sources (Google Spreadsheet, Excel, CSV, etc) are non-server-side tables and they pull all the data from the source, add it to the page, and then split the table into table-pages using javaScript. While this is OK for small datasets (up to 2.000 - 3.000 cells), it can slow down or even break the page if the data gets bigger.

You can try the following, but I don't have high hopes that you'll be able to pull a large dataset even with these modifications:

1. If you're using the API method:

This error is returned by the function wp_remote_get which uses cURL in the background. The client's server doesn't have time to manage the data from Google's API in 5 seconds (which is the default setting in WordPress).

That limit can be increased using a hook https://wordpress.stackexchange.com/questions/341357/wp-remote-get-curl-error-28-only-on-same-domain. Instead of "15" set it to "100", just in case.

If you get this error because of the WordPress hook extend_http_request_timeout, you need to remove it from your functions.php file and then checkout solutions for the first initial error for curl error 28 - Operation timed out ...

https://www.wpbeginner.com/wp-tutorials/how-to-fix-curl-error-28-connection-timed-out-after-x-milliseconds/

2. If you're using the old method (without Google's API credentials) the timeout limit is set to 25 in file wp-content/plugins/wpdatatables/source/class.wdttools.php on line 198.

This can be overwritten with the hook wpdatatables_curl_get_data. For example:

function filterCURLOptions($data, $ch, $url){
   $new_ch = curl_init();
   $timeout = 1000;
   $agent = 'Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0';
        curl_setopt($new_ch, CURLOPT_URL, $url);
        curl_setopt($new_ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($new_ch, CURLOPT_CONNECTTIMEOUT, $timeout);
        curl_setopt($new_ch, CURLOPT_USERAGENT, $agent);
        curl_setopt($new_ch, CURLOPT_REFERER, site_url());
        curl_setopt($new_ch, CURLOPT_FOLLOWLOCATION, true);
        $data = curl_exec($new_ch);
            if (curl_error($new_ch)) {
                $error = curl_error($new_ch);
                curl_close($new_ch);
                throw new Exception($error);
            }
            if (strpos($data, '<title>Moved Temporarily</title>')) {
                throw new Exception(__('wpDataTables was unable to read your Google Spreadsheet, probably it is not published correctly. <br> You can publish it by going to <b>File -> Publish to the web</b> ', 'wpdatatables'));
            }
            $info = curl_getinfo($new_ch);
            curl_close($new_ch);
            if ($info['http_code'] === 404) {
                return NULL;
            }
   
    return $data;
}
add_filter('wpdatatables_curl_get_data','filterCURLOptions', 10, 3);

This needs to go to the functions.php file of your theme or the child theme (depending on what you're using).

What do you mean Anna?

Hooks and filters are usually added to functions.php file of your theme or child theme.

Hello Anna

There is nothing new I can suggest about this issue.

This error only appears in Google Sheets-based tables, and it's coming from Google, not wpDataTables. 

Google's server, to which wpDataTables is connecting has its own method of establishing the connection, and we're using PHPs logic to connect to it. If there are errors your server returns, those are returned by the server, and only displayed by wpDataTables.

Unfortunately, this response from 3 weeks ago is still the only response I can provide. Our developers are working on bypassing this issue but since it's coming from Google, other than increasing the quota in your Google account, I don't believe there's anything more they will be able to do in the near future.