Hi @toolidoo,

I am sorry but there could be too many reasons why a plugin cannot be activated and respectively we can only offer you a couple of initial steps that would hopefully narrow a bit the use-case.

I would start by checking with the hosting provider to make sure that the following NextGen Gallery plugin’s requirements are met: https://www.imagely.com/docs/requirements/

If the above wouldn’t help, you may need to enable WordPress debug mode by editing your site’s wp-config.php file by FTP and replacing the following line:

define('WP_DEBUG', false);

with this

ini_set('log_errors','On');
ini_set('display_errors','On');
ini_set('error_reporting', E_ALL );
define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', true);

Save the changes and try to install and activate NextGen again to see if the error will be more relevant and provide us with that error code. If the error still remains irrelevant, please login by FTP to your domain’s file server, navigate to "wp-content" folder and edit the error_log.txt file then look for the most recent Fatal or Syntax error code. Provide us with that line.

Thanks