Unexpected admin errors, blank screens, or broken Security Ninja screens are often a conflict with another plugin. Isolate plugins like this:
- Take a backup (or work on staging).
- Go to Plugins → Installed Plugins.
- Deactivate every plugin except Security Ninja.
- Retest the problem.
- If it still fails, it is probably not a plugin conflict (theme, host, or core may be involved).
- If it works, reactivate plugins one by one and retest after each.
- When the issue returns, you have found a likely conflict.
Report both plugin names and versions to Security Ninja support, and tell the other plugin’s author as well.
Related: How to locate JavaScript conflicts, Disable the firewall.