Re: Incorrect access detected, this server may be accessed only through "http://192.168.2.2:8181/moodle" address, sorry. Please notify server administrator.

HTTP_REVERSE_VIA     TMG
HTTP_HOST     hostobsecured.elgounanursing.local:8181
SERVER_ADDR     192.168.2.2
SERVER_PORT     8181
REMOTE_ADDR     192.168.2.1

Project is named moodle and points to http://moodle ... which won't work for sure, me thinks.

https://docs.moodle.org/30/en/Reverse_proxy_frontend

You also need to research shutting down (never to launch on reboot) IIS *OR* don't run apache.   Run IIS!

'spirit of sharing', Ken