PDF Service Manager not enabling on Azure Container Instance Linux Server

Sorry. It wasn't readily clear you were using the Adobe CF container image. So have you followed the details and examples offered by Adobe for how to run the pdf service within the cf container? See https://helpx.adobe.com/coldfusion/using/docker-images-coldfusion.html.

Note how it's necessary to run NOT ONLY the CF container, but also you need to run the separate CF "addons" container, and point the CF container at that. (This is just a twist on what I was saying above: how with traditional CF installation, that too has both CF itself and a separate "add on" service.)

The doc page I point to above discusses how to setup a docker compose file that has both running, and also shows setting the environment variables in the CF container that point to the addons running in the other container.

If you would like a different presentation of a working example, I offer one myself, as part of my "Awesome CF Compose" project on github. You will see there that I offer many different examples of the CF Docker images, including one specifically with the heading, "ColdFusion with Solr and and PDFg (CFHTML2PDF) features enabled".

You'll see it's the docker-compose.yml (which may be all you really need), which shows the setup of the two containers, as well as the env vars needed for each, including naming the cf2021 module called htmltopdf which is needed to use the PDF feature. (You may already know about that, as you show using the PDF Service page working in the admin.)

Finally, I also show there an example with a cfhtmltopdf call that works, using those containers, in a subfolder called demo-pdfg, within the container's /app, which you may already know is where the CF images look for code to run within the container.

Let us know if that gets you going.