FailedToExecuteCommand error on specific PDF files

I am using the Regenerate Thumbnails to process media on a WordPress site. These include PDF files. Thumbnails are successfully created for all but a couple of similar PDF files in the Media library. These fail with the error:

ERROR: FailedToExecuteCommand `’gs’ -q -dQUIET -dSAFER -dBATCH -dNOPAUSE -dNOPROMPT -dMaxBitmap=500000000 -dAlignToPixels=0 -dGridFitTT=2 ‘-sDEVICE=pngalpha’ -dTextAlphaBits=4 -dGraphicsAlphaBits=4 ‘-r128x128’ -dFirstPage=1 -dLastPage=1 ‘-sOutputFile=/tmp/magick-5286745U_EcJ7RnxR%d’ ‘-f/tmp/magick-52867syBOC1kidKAl’ ‘-f/tmp/magick-52867t2__2QPzxaEP” (-1) @ error/delegate.c/ExternalDelegateCommand/462

This same files process successfully on our staging server, but fail as above in the deployment environment (SiteGround shared hosting).

Any advice on how to further troubleshoot this would be appreciated.