Thumbnails not being generated for PDF files

I have installed all the required extensions like ImageMagick, Imagick, and Ghostscript. I used a plugin to test the requirements and everything passed.

ImageMagick:     Installed
Imagick:     Installed
Ghostscript:     Installed
WordPress = 4.7:    Installed

GPL Ghostscript 9.27 (2019-04-04)

But for some reason, WordPress does not generate thumbnails for PDF files while uploading them directly from the media manager or from the post editor. I also tried using the Regenerate Thumbnails plugin but it did not scan for the PDF file.

I have hosted my website on the Plesk server. Is there anything that I might be missing?