Failed at step EXEC spawning

Hello
host OS version: CentOS Linux release 7.4.1708 (Core)
device concerned: PortServer TS2
After following steps described in https://forms.na1.netsuite.com/app/site/hosting/scriptlet.nl?script=457&deploy=2&compid=818164&h=5928a16f2b6f9582b799&articleid=923 to compile and install 40002086_Y.src.rpm, i always get the error digi.service failed with error ExecStart=/opt/meteo/bin/digi.sh (code=exited, status=203/EXEC)despite the digi.sh file exists in /opt/meteo/bin/

the /var/log/messages shows:
Mar 21 12:05:58 testcommb systemd: Starting DIGIPORT…
Mar 21 12:05:58 testcommb systemd: Failed at step EXEC spawning /opt/meteo/bin/digi.sh: No such file or directory
Mar 21 12:05:58 testcommb systemd: digi.service: main process exited, code=exited, status=203/EXEC
Mar 21 12:05:58 testcommb systemd: Unit digi.service entered failed state.
Mar 21 12:05:58 testcommb systemd: digi.service failed.

the digi.sh file is as below


#!/bin/bash
/usr/bin/dgrp/config/dgrp_cfg_node init -v -v -e never 1 11.11.11.35 2
/usr/bin/dgrp/config/dgrp_cfg_node start 1 11.11.11.35 2
the digi.sh file is as below

chmod 666 /dev/dgrp


and the digi.service is as below


[Unit]
Description=DIGIPORT
#After=syslog.target

[Service]
Type=simple
GuessMainPID=yes
ExecStart=/opt/meteo/bin/digi.sh
KillMode=process

Restart=on-failure
#Restart=always
RestartSec=10s

[Install]
WantedBy=multi-user.target


To be noted: same result if compiling/installing the driver using dgrp-1.9-37_y1p.tgz.rpm

thank you for help