Hi, there’s no error log file in the wordpress root (where wp-config is). ??
My host fortunately has a diagnostics fucntion, and there are some php errors relevant to Loginizer (they seem to produce a 500 error). Sample of a few lines:
mysitexx.org.uk [Thu Sep 21 12:19:29 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Fatal error: Call to undefined function wp_doing_ajax() in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/init.php on line 449\n'
mysitexx.org.uk [Thu Sep 21 12:19:58 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Fatal error: Call to undefined function wp_doing_ajax() in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/init.php on line 449\n'
mysitexx.org.uk [Thu Sep 21 12:20:19 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Fatal error: Call to undefined function wp_doing_ajax() in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/init.php on line 449\n'
mysitexx.org.uk [Thu Sep 21 12:21:26 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Fatal error: Call to undefined function wp_doing_ajax() in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/init.php on line 449\n'
mysitexx.org.uk [Thu Sep 21 12:22:01 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Warning: include_once(/home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/loginizer.php): failed to open stream: No such file or directory in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-settings.php on line 215\nPHP message: PHP Warning: include_once(): Failed opening '/home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/loginizer.php' for inclusion (include_path='.:/usr/share/pear') in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-settings.php on line 215\n'
mysitexx.org.uk [Thu Sep 21 12:22:07 2023] [error] [client 92.9.150.27:0] AH01071: Got error 'PHP message: PHP Fatal error: Call to undefined function wp_doing_ajax() in /home/sites/11b/b/b7e8ca7d2e/public_html/wp-content/plugins/loginizer/init.php on line 449\n'
There are quite a few more lines, all repeating the ‘call to undefined function wp_doing_ajax()’ line.