Hi! I have a little problem. Users cannot unsubscribe.
After clicking the "unsubscribe" link, the following message appears:
Warning: Undefined array key "url" in /home/arktour/ftp/wp-content/plugins/newsletter/profile/profile.php on line 41
Warning: Cannot modify header information - headers already sent by (output started at /home/arktour/ftp/wp-content/plugins/newsletter/profile/profile.php:41) in /home/arktour/ftp/wp-includes/pluggable.php on line 1355
Warning: Cannot modify header information - headers already sent by (output started at /home/arktour/ftp/wp-content/plugins/newsletter/profile/profile.php:41) in /home/arktour/ftp/wp-includes/pluggable.php on line 1358
What should I improve to make it work properly?
Best wishes
Arkadius