Trying to update jetpack crashes site

Could you try to log in to your site via FTP or CPanel, delete the existing Jetpack plugin folder, and reinstall the plugin manually as explained here:
https://codex.www.ads-software.com/Managing_Plugins#Manual_Plugin_Installation

You’ll find the Jetpack plugin folder here:

wp-content
   plugins
     jetpack - DELETE THIS FOLDER

If you’re not sure how to do this, you can ask your hosting company for help. They should also have documentation explaining how to edit or remove files from your site using FTP or a File Manager in your admin panel.

If you continue to experience issues after the manual update, could you add the following to your site’s wp-config.php file?

define( 'WP_DEBUG', true );

if ( WP_DEBUG ) {

        @error_reporting( E_ALL );
        @ini_set( 'log_errors', true );
        @ini_set( 'log_errors_max_len', '0' );

        define( 'WP_DEBUG_LOG', true );
        define( 'WP_DEBUG_DISPLAY', false );
        define( 'CONCATENATE_SCRIPTS', false );
        define( 'SAVEQUERIES', true );

}

Your wp-config.php file may already include a line that says “define(‘WP_DEBUG’, false);”. You can remove it, and replace it by the code above.

Once you’ve done so, try to trigger that error you’ve been having and then check the wp-content/debug.log file for errors. You can paste the results here. You can then replace define('WP_DEBUG', true); by define('WP_DEBUG', false); in the code above.

Thanks!