Linux Coldfusion2021 No Service manager is available for PDFg

I realize this is a couple of years on, but in case it may help anyone, I had an instance where I got this error ("No Service manager is available"), and the solution was actually rather simple: on the "PDF service" page of the CF admin, make sure that the "enable" (or "play") button is on (and the "stop" button is not).

In other words, in at least one case I helped with today, the problem was simply that the PDF service was indeed NOT enabled. But there's no words to convey that (in the table to the right of the service). There are only these tiny UI elements, and it can be easy to miss whether the service is enabled or not. And what's also confusing is that the service will "verify" if you try it (reporting "ok"), but that's NOT checking whether the service is ENABLED in CF, only if the service it points to (the add-on service) is running.

Now, if instead you try to run the cfhtmltopdf and get instead the error, "Error occurred while generating PDF", that's a DIFFERENT problem. Often the solution is one I offered in a couple of other places, such as https://stackoverflow.com/a/77327211/90802.

Try the solution offered here: https://community.adobe.com/t5/coldfusion-discussions/installing-coldfusion-add-on-services-pdfg-for-linux-success/td-p/12103936 

But before all that, do a quick check. Open the ColdFusion Administrator. Go to Data & Services > PDF Service. 

There should be a service manager, named Localhost, registered under the section PDF Service Managers. Is it enabled? To be sure, click on the Enabled button.

Does that help?