Add the IP address of the nagios server to nrpe.cfg, for my case my configuration file is located in /usr/local/nagios/etc/nrpe.cfg, if your cfg file is located else where use this command to find find / -name nrpe.cfg

Search for the parameter allowed_hosts:

# (i.e. 192.168.1.0/24) are also supported. Hostname wildcards are not currentl$
# supported.
#
# Note: The daemon only does rudimentary checking of the client's IP
# address.  I would highly recommend adding entries in your /etc/hosts.allow
# file to allow only the specified host to connect to the port
# you are running this daemon on.
#
# NOTE: This option is ignored if NRPE is running under either inetd or xinetd

allowed_hosts=127.0.0.1 192.168.0.140

append the nagios server ip address.