When you get below error messages, do follow steps to disable the service.
%Error opening tftp://255.255.255.255/network-confg (Socket error)
%Error opening tftp://255.255.255.255/cisconet.cfg (Socket error)
%Error opening tftp://255.255.255.255/3620-confg (Socket error)
%Error opening tftp://255.255.255.255/3620.cfg (Socket error)
Cisco_Router#config terminal
Cisco_Router(config)#no service config
Cisco_Router(config)#exit
Cisco_Router#copy running-config startup-config