REST API problem

Hi,
I’ve installed Ninjafirewall on a site and it seems to be working properly.

However, when I run WP Site Health, I get the following…

The REST API request failed due to an error.
Error: [] cURL error 28: Operation timed out after 10000 milliseconds with 0 bytes received

I have disabled all plugins and changed the theme and added plugins back one at a time and its Ninjafirewall that triggers the message.

If Ninjafirewall is enabled in the Firewall Options – the problem exists.(there is no problem evident in the log files)

If Ninjafirewall is enabled and debug is turned on – the problem exists. (no problem shows in the Firewall log)

If Ninjafirewall is active and disabled in Firewall Options – the problem goes away.

Any idea what’s going on? This problem doesn’t seem to occur on other websites where I have Ninjafirewall installed.