Blank page after saving settings

A blank page usually means a PHP error that is not shown on screen.

A white screen is not an absence of information, it is an error that PHP was told not to display. The fix is to make the message visible, then act on it.

Turn the error into a message

In Joomla, open System, Global Configuration, Server and set Error Reporting to Maximum, then reload the page that failed. Set it back to Default or None once you are done, because visitors should never see raw errors.

Read the server log instead

If the screen stays blank, the detail is in the PHP error log. Typical locations:

• cPanel hosting: ~/logs/error_log or an error_log file beside the script.
• Local development: the logs folder of your PHP install.
• Joomla itself: administrator/logs/error.php when logging is enabled.

Frequent causes

• Memory exhausted. "Allowed memory size of N bytes exhausted" needs a higher memory_limit.
• PHP version mismatch. A syntax error on an otherwise valid file usually means the extension needs a newer PHP.
• Conflicting plugin. Disable third party plugins one at a time to find it.

Paste the log line into your ticket along with your Joomla and PHP versions. One line of log detail is worth several rounds of guessing.