Try to stop some deamons, may be some of them stop it… or reboot the NAS:
/etc/init.d/wdphotodbmergerd stop
/etc/init.d/wdmcserverd stop
/etc/init.d/wdnotifierd stop
/etc/init.d/wddispatcherd stop
killall crond
drive_sleep.sh off
sleep 1
drive_sleep.sh on
hd_standby.sh 5
It works!
Here the link => Very Slow Dashboard access on My Cloud Mirror 8TB 2 Gen