passenger-memory-stats works, but passenger-status does not (Passenger + Apache)

I have an application running on Passenger+Apache. (It's running fine.)

When I run passenger-status, though, it gives ERROR: Phusion Passenger doesn't seem to be running.

I've checked the Apache config to confirm that I'm running the proper passenger-status executable:

PassengerRoot /usr/local/rvm/gems/ruby-1.9.3-p547@mygemset/gems/passenger-4.0.53

What could be wrong this this installation or config?

Strangely, passenger-memory-stats looks to me to output accurate process information:

Version: 4.0.53
Date   : 2020-07-28 16:32:36 -0700

---------- Apache processes ----------
PID    PPID   VMSize    Private  Name
--------------------------------------
10093  1      254.8 MB  0.3 MB   /usr/sbin/httpd -DFOREGROUND
10132  10093  254.9 MB  0.4 MB   /usr/sbin/httpd -DFOREGROUND
10134  10093  254.9 MB  0.3 MB   /usr/sbin/httpd -DFOREGROUND
10135  10093  254.9 MB  0.4 MB   /usr/sbin/httpd -DFOREGROUND
10136  10093  254.8 MB  0.2 MB   /usr/sbin/httpd -DFOREGROUND
10137  10093  254.9 MB  0.3 MB   /usr/sbin/httpd -DFOREGROUND
### Processes: 6
### Total private dirty RSS: 1.97 MB


-------- Nginx processes --------

### Processes: 0
### Total private dirty RSS: 0.00 MB


----- Passenger processes -----
PID    VMSize    Private  Name
-------------------------------
10114  212.2 MB  0.3 MB   PassengerWatchdog
10117  491.8 MB  0.4 MB   PassengerHelperAgent
10123  215.7 MB  0.9 MB   PassengerLoggingAgent
### Processes: 3
### Total private dirty RSS: 1.54 MB