headers already sent, after activation

Hello

I get those error messages after activation :

header information – headers already sent by (output started at /home/www/inzemouvorg/wp-content/plugins/ecards-lite/ecards.php:38) in /home/www/inzemouvorg/wp-includes/option.php on line 820

Warning: Cannot modify header information – headers already sent by (output started at /home/www/inzemouvorg/wp-content/plugins/ecards-lite/ecards.php:38) in /home/www/inzemouvorg/wp-includes/option.php on line 821

I put this in the wp-config.php file as temporary solution
error_reporting(0);
@ini_set(‘display_errors’, 0);

Can you care for a definitive solution ?
Thanks,

Delvasse

https://ww.wp.xz.cn/plugins/ecards-lite/