One of the possible cause is that you are using admin.conf which had been used for IHSv8.5 or earlier version. Please check <IHSv9_ROOT>/conf/admin.conf and you will see the following lines.
# Use worker if the current build uses dynamic MPMs.
<ifModule !worker.c>
LoadModule mpm_worker_module modules/mod_mpm_worker.so
</ifModule>
And I assume this part is missing in your admin.conf. Kindly try to add the lines and see if you can start IHS admin server.
------------------------------
Yoshiki Yamada
IBM Japan
------------------------------
Original Message:
Sent: Tue April 18, 2023 10:22 PM
From: Yoshiki Yamada
Subject: adminctl fails with "AH00534: httpd: Configuration error: No MPM loaded"
When I tried to start IHS admin server, it failed with the message below. What is the possible cause?
```
/opt/IBM/HTTPServer90/bin/adminctl -k start
AH00534: httpd: Configuration error: No MPM loaded.
```
------------------------------
Yoshiki Yamada
IBM Japan
------------------------------