A blank page indicates that two things happened:
- A fatal error occured while creating the web page.
- Your web-server (e.g. apache, nginx, IIS) is configured not to display fatal errors on the screen.
Typical causes of fatal errors are:
- File permissions. webtrees needs to be able to write to all the files and subfolders in the folder /data/
- Running out of disk space. You can check if this is a problem by uploading (and then deleting) a large file to the server using FTP.
- Running out of CPU time. You can identify these because the error does not appear until the time limit is reached.
- Running out of memory. This can be caused by program errors or by trying to process a lot of data at once. For example, trying to list many thousand individuals at the same time.
- Incompatible software. For example, using PHP 7.3 with software that was designed for PHP 7.4.
- Trying to use a PHP function that has been blocked by your web-host. For example, the function needed to send mail can be blocked.
Generally when a fatal error occurs, the web-server will write a detailed error message to a log file. You need to find this error log. Without it, it will be very difficult to fix the problem.
Note that your web-server will produce two log files. One is the access log and the other is the error log. You want the error log.
If you cannot find your error log, you should contact your webhosting provider for assistance.
Alternatively, if your server uses .htaccess files, try adding the following lines:
php_flag display_errors on
php_flag display_startup_errors on
php_value error_reporting -1