You can simply turn off these warnings by following these steps:
1. Navigate to your wordpress root directory.
2. Edit wp-config.php file and add the following code in the next line after the php tag: error_reporting(0);
2. Make sure that WP_DEBUG is set to false in wp-config.php file
I hope that will help!
This reply was modified 6 years, 7 months ago by Maninder.
If your server configurations are very good then you do not need to worry about this. If not, then i recommend you to scan the files for malicious code on your server and then harden the security of your site. He might gained access to your site. You blocked his IP address but he can use another IP address.
I recommend you to download your site files and database in your computer. Then check your files. There might be malicious code installed on it. You can post content of wp-content/plugins/nextgen-facebook/nextgen-facebook.php file code here and i’ll let you know about this file.