Error: Exception: Temporary files directory "/data/sites/web/ventobe/subsites/vento.be/httpdocs/site/assets/cache/WireTempDir/.RockPdf/0//ttfontdata" is not writable (in /data/sites/web/ventobe/subsites/vento.be/httpdocs/site/modules/RockPdf/vendor/mpdf/mpdf/src/Cache.php line 17)

#0 /data/sites/web/ventobe/subsites/vento.be/httpdocs/site/modules/RockPdf/vendor/mpdf/mpdf/src/Mpdf.php(984): Mpdf\Cache->__construct('/data/sites/web...')
#1 /data/sites/web/ventobe/subsites/vento.be/httpdocs/site/modules/RockPdf/RockPdf.module.php(38): Mpdf\Mpdf->__construct(Array)
#2 /data/sites/web/ventobe/subsites/vento.be/httpdocs/site/modules/RockPdf/RockPdf.module.php(22): ProcessWire\RockPdf->settings(Array)
#3 /data/sites/web/ventobe/subsites/vento.be/httpdocs/wire/core/Modules.php(624): ProcessWire\RockPdf->init()
#4 /data/sites/web/ventobe/subsites/vento.be/httpdocs/wire/core/Modules.php(1336): ProcessWire\Modules->initModule(Object(ProcessWire\RockPdf), Array)
#5 /data/sites/web/ventobe/subsites/vento.be/httpdocs/wire/core/M

This error message was shown because: site is in debug mode. ($config->debug = true; => /site/config.php). Error has been logged.