ImageMagick not authorized to convert PDF to an image

emcconville is correct. More specifically edit the Imagemagick policy.xml file to uncomment this line:

  <!-- <policy domain="module" rights="none" pattern="{PS,PDF,XPS}" /> -->

And change it from rights="none" to rights="read|write"

  <policy domain="module" rights="read|write" pattern="{PS,PDF,XPS}" />

This was a recent addition to the policy.xml file, I believe, due to a security flaw found in the Ghostscript delegate. I think that flaw has now been fixed in the current version of Ghostscript, which is 9.25.

NOTE: On some systems the policy line will have domain="coder" rather than domain="module"

Quick and easy solution:

sudo mv /etc/ImageMagick-6/policy.xml /etc/ImageMagick-6/policy.xml.off

When done, you can restore the original with

sudo mv /etc/ImageMagick-6/policy.xml.off /etc/ImageMagick-6/policy.xml

I am using Dockerfile to update an image, and suddenly I got the policy.xml file in my way. although the version of Ubuntu (xenial) was the same and ImageMagick as well.

I ended up removing the single line causing my problem.

RUN sed -i 's/^.*policy.*coder.*none.*PDF.*//' /etc/ImageMagick-6/policy.xml

hope this helps someone