You must set the policy of ImageMagick to allow PDF read. See https://stackoverflow.com/questions/52703123/override-default-imagemagick-policy-xml
ImagickException: FailedToExecuteCommand `'gs' -sstdout=%stderr -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 '-sDEVICE=pngalpha' -dTextAlphaBits=4 -dGraphicsAlphaBits=4 '-r150x150' -dPrinted=false '-sOutputFile=/tmp/magick-njZmkpIUC7w0FJGRj_87ayI51yFQDcV1%d' '-f/tmp/magick-TmrokXG1dlUw06Rdoqho5fRzv7ajiF0T' '-f/tmp/magick-NJW6WbKLjrq6EZ057RMWwGGyM-I3A5F2'' (256) @ error/ghostscript-private.h/ExecuteGhostscriptCommand/75 in /home/zeidacadmey/public_html/e/mod/securepdf/view.php:98
Stack trace:
#0 /home/zeidacadmey/public_html/e/mod/securepdf/view.php(98): Imagick->readImageBlob()
#1 {main}