If you see the error above after trying to activate your license key on the license settings page, this means that your server could not connect to https://www.mapsmarker.com for the license validation.
Please first check if you are using at least v1.7, which includes a workaround for servers with outdated SSL libraries, that are needed to connect to the license API on mapsmarker.com. If you are using a version below 1.7 and also do not see that there is an update available, your server is very likely to be affected from this issue. To solve this, please update manually once to the latest version by downloading the current plugin package from https://mapsmarker.com/download-pro and overwritting the files on your webserver via FTP. Future updates should then work again as usual.
If updating to v1.7 or above did not solve the issue, please ask your hoster for help. There might be special security precautions preventing your server from communicating directly with https://www.mapsmarker.com (GET requests, Port 443)
It could also be that your server only allows direct connection through a proxy (you can verify this if you are not receiving any WordPress core or plugin updates). If this is the case, the proxy server has to be configured in wp-config.php (please ask your hoster for details about your proxy):
define('WP_PROXY_HOST', '192.168.xx.xxx'); define('WP_PROXY_PORT', '8080'); define('WP_PROXY_USERNAME', 'my_user_name'); define('WP_PROXY_PASSWORD', 'my_password'); define('WP_PROXY_BYPASS_HOSTS', 'localhost, www.example.com');
If that also does not help, please open a support ticket and we will be glad to help you solving your issue!