pngquant is missing

Hello,
I’ve installed your plugin on my website.

I tried to activate Lossy PNG optimization but pngquant is missing.
Is there something I can do?

jpegtran: Installed?version: Independent JPEG Group's JPEGTRAN, version 9a 19-Jan-2014
optipng: Installed?version: OptiPNG 0.6.4: Advanced PNG optimizer.
pngquant: Missing
safe mode: Off??exec(): Enabled??
Graphics libraries - only need one, used for conversion, not optimization
GD: Installed??Imagemagick 'convert': Installed
Only need one of these:
finfo: Installed??getimagesize(): Installed??mime_content_type(): Installed

This is the debug log:

Debug Log
hosting-user
EWWW IO version: 222
WP version: 4.1.1
ewww_image_optimizer_admin_init()
ewww_image_optimizer_init()
ewww_image_optimizer_cloud_init()
ewww_image_optimizer_jpg_background()
ewww_image_optimizer_jpg_quality()
ewww_image_optimizer_cloud_key_sanitize()
ewww_image_optimizer_cloud_verify()
sanitize (verification) failed
ewww_image_optimizer_aux_paths_santitize()
ewww_image_optimizer_exec_init()
ewww_image_optimizer_install_tools()
Checking/Installing tools in /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/
wp-content/ewww permissions: 0775
ewww_image_optimizer_install_paths()
CPU architecture: x86_64
generated paths:
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/jpegtran-linux64
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/optipng-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/gifsicle-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/pngquant-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/cwebp-linux864
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp
64-bit linux detected while installing tools
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran-alt: 8e4a09bb04ba001f5f16651ae8594f7f
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp-alt: eb3a5b6eae54140269ed6dcf6f792d37
Linux/UNIX style OS, checking permissions
jpegtran permissions: 0755
gifsicle permissions: 0755
optipng permissions: 0755
pngquant permissions: 0755
webp permissions: 0755
ewww_image_optimizer_notice_utils()
ewww_image_optimizer_exec_check()
disable_functions = pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,
suhosin_blacklist =
ewww_image_optimizer_safemode_check()
safe_mode =
ewww_image_optimizer_path_check()
found /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran, testing...
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran: 47c39feae0712f2996c61e5ae639b706
ewww_image_optimizer_mimetype()
testing mimetype: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
finfo_file: application/x-executable
ewww_image_optimizer_tool_found()
testing case: j at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran: Independent JPEG Group's JPEGTRAN, version 9a 19-Jan-2014
optimizer found
found /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng, testing...
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng: 31698da4f5ca00b35e910c77acae65bb
ewww_image_optimizer_mimetype()
testing mimetype: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng
finfo_file: application/x-executable
ewww_image_optimizer_tool_found()
testing case: o at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng: 1: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng: ELF?4?: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: o at optipng
optipng: OptiPNG 0.6.4: Advanced PNG optimizer.
optimizer found
found /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle, testing...
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle: 58f42368e86a4910d101d37fee748409
ewww_image_optimizer_mimetype()
testing mimetype: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle
finfo_file: application/x-executable
ewww_image_optimizer_tool_found()
testing case: g at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle: 1: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle: ELF?4?@: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: g at gifsicle
gifsicle: sh: 1: gifsicle: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: g at /usr/bin/gifsicle
/usr/bin/gifsicle: sh: 1: /usr/bin/gifsicle: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: g at /usr/local/bin/gifsicle
/usr/local/bin/gifsicle: sh: 1: /usr/local/bin/gifsicle: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: g at /usr/gnu/bin/gifsicle
/usr/gnu/bin/gifsicle: sh: 1: /usr/gnu/bin/gifsicle: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: g at /usr/syno/bin/gifsicle
/usr/syno/bin/gifsicle: sh: 1: /usr/syno/bin/gifsicle: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at pngout
pngout: sh: 1: pngout: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/bin/pngout
/usr/bin/pngout: sh: 1: /usr/bin/pngout: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/local/bin/pngout
/usr/local/bin/pngout: sh: 1: /usr/local/bin/pngout: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/gnu/bin/pngout
/usr/gnu/bin/pngout: sh: 1: /usr/gnu/bin/pngout: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/syno/bin/pngout
/usr/syno/bin/pngout: sh: 1: /usr/syno/bin/pngout: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at pngout-static
pngout-static: sh: 1: pngout-static: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/bin/pngout-static
/usr/bin/pngout-static: sh: 1: /usr/bin/pngout-static: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/local/bin/pngout-static
/usr/local/bin/pngout-static: sh: 1: /usr/local/bin/pngout-static: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/gnu/bin/pngout-static
/usr/gnu/bin/pngout-static: sh: 1: /usr/gnu/bin/pngout-static: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: p at /usr/syno/bin/pngout-static
/usr/syno/bin/pngout-static: sh: 1: /usr/syno/bin/pngout-static: not found
tool not found
found /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant, testing...
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant: 46bb066d676bf94cbfd78bdc0227e74e
ewww_image_optimizer_mimetype()
testing mimetype: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant
finfo_file: application/x-executable
ewww_image_optimizer_tool_found()
testing case: q at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant: 1: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant: Syntax error: word unexpected (expecting ")")
tool not found
ewww_image_optimizer_tool_found()
testing case: q at pngquant
pngquant: sh: 1: pngquant: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: q at /usr/bin/pngquant
/usr/bin/pngquant: sh: 1: /usr/bin/pngquant: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: q at /usr/local/bin/pngquant
/usr/local/bin/pngquant: sh: 1: /usr/local/bin/pngquant: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: q at /usr/gnu/bin/pngquant
/usr/gnu/bin/pngquant: sh: 1: /usr/gnu/bin/pngquant: not found
tool not found
ewww_image_optimizer_tool_found()
testing case: q at /usr/syno/bin/pngquant
/usr/syno/bin/pngquant: sh: 1: /usr/syno/bin/pngquant: not found
tool not found
found /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp, testing...
ewww_image_optimizer_md5check()
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp: 9b6f13ce6ee5a028cbd2765e2d53a1d7
ewww_image_optimizer_mimetype()
testing mimetype: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp
finfo_file: application/x-executable
ewww_image_optimizer_tool_found()
testing case: w at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp: 0.4.1
optimizer found
using: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
using: optipng
using: /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp
ewww_image_optimizer_settings_script()
images to check for savings: 1950
ewww_image_optimizer_network_settings_saved()
ewww_image_optimizer_options()
ewww_image_optimizer_install_paths()
CPU architecture: x86_64
generated paths:
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/jpegtran-linux64
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/optipng-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/gifsicle-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/pngquant-linux
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/plugins/ewww-image-optimizer/cwebp-linux864
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/optipng
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/gifsicle
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/pngquant
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/cwebp
ewww_image_optimizer_tool_found()
testing case: j at /srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran
/srv/data/web/vhosts/www.pinhopper.com/htdocs/wp-content/ewww/jpegtran: Independent JPEG Group's JPEGTRAN, version 9a 19-Jan-2014
optimizer found
ewww_image_optimizer_tool_found()
testing case: o at optipng
optipng: OptiPNG 0.6.4: Advanced PNG optimizer.
optimizer found
ewww_image_optimizer_safemode_check()
safe_mode =
ewww_image_optimizer_exec_check()
disable_functions = pcntl_alarm,pcntl_fork,pcntl_waitpid,pcntl_wait,pcntl_wifexited,pcntl_wifstopped,pcntl_wifsignaled,pcntl_wexitstatus,pcntl_wtermsig,pcntl_wstopsig,pcntl_signal,pcntl_signal_dispatch,pcntl_get_last_error,pcntl_strerror,pcntl_sigprocmask,pcntl_sigwaitinfo,pcntl_sigtimedwait,pcntl_exec,pcntl_getpriority,pcntl_setpriority,
suhosin_blacklist =
ewww_image_optimizer_gd_support()
GD found, supports:
GD Version: 2.0.36
FreeType Support: 1
FreeType Linkage: with freetype
T1Lib Support:
GIF Read Support: 1
GIF Create Support: 1
JPEG Support: 1
PNG Support: 1
WBMP Support: 1
XPM Support:
XBM Support:
JIS-mapped Japanese Font Support:
ewww_image_optimizer_tool_found()
testing case: i at convert
convert: Version: ImageMagick 6.7.7-10 2014-03-08 Q16 https://www.imagemagick.org
imagemagick found
ewww_image_optimizer_tool_found()
testing case: n at nice
nice: 0
nice found
ewww_image_optimizer_jpg_background()
ewww_image_optimizer_jpg_background()
ewww_image_optimizer_jpg_quality()
--180--

Thanks in advance.

https://www.ads-software.com/plugins/ewww-image-optimizer/