Edit the /etc/systemnd/sleep.conf file as shown below:

[Sleep]
AllowSuspend=no
AllowHibernation=no
AllowSuspendThenHibernate=no
AllowHybridSleep=no
#SuspendMode=
#SuspendState=mem standby freeze
#HibernateMode=platform shutdown
#HibernateState=disk
#HybridSleepMode=suspend platform shutdown
#HybridSleepState=disk
#HibernateDelaySec=
#SuspendEstimationSec=60min