Hello,
It seems you have installed the Debian Apache server package and it is causing collisions between it and the Apache shipped in the stack. Please note that Bitnami Stacks are completely self-contained and run independently of the rest of the software or libraries installed on your system.
Please run the following commands to enable again the correct Apache:
- Stop the Debian Apache server:
sudo systemctl stop apache2
- Disable the Debian Apache server to start on the reboots:
sudo systemctl disable apache2
- Start the services of your stack:
sudo /opt/bitnami/ctlscript.sh start
Once you have recovered the access to your WordPress application, if you want to migrate it to a Multisite installation we recommend you to launch a new instance with WordPress Multisite and migrate your current installation to it. In this guide you can find the detailed steps you need to follow to achieve that:
https://docs.bitnami.com/installer/how-to/combine-wordpress-multisite/
Regards,
Jose