If you have access to the operating systems running on the servers (you did not indicate which), you can program the ILO using the hponcfg
utility.
The things you can do here are listed in the command's help, with the "-r" flag actually resetting the ILO to default. I would try something less sever first, like "-w" which writes the ILO's configuration to a file. Maybe your device obtained a DHCP address or lost some settings.
hponcfg -?
hponcfg -h
hponcfg -m minFw
hponcfg -r [-m minFw ]
hponcfg [-a] -w filename [-m minFw]
hponcfg -g [-m minFw]
hponcfg -f filename [-l filename] [-s namevaluepair] [-v] [-m minFw]
hponcfg -i [-l filename] [-s namevaluepair] [-v] [-m minFw]
-h, --help Display this message
-? Display this message
-r, --reset Reset the RILOE II/iLO to factory default
-f, --file Get/Set RILOE II/iLO configuration from "filename"
-i, --input Get/Set RILOE II/iLO configuration from the XML input
received through the standard input stream.
-w, --writeconfig Write the RILOE II/iLO configuration to "filename"
-a, --all Capture complete iLO configuration to the file.
This should be used along with '-w' option
-l, --log Log replies to "filename"
-v, --xmlverbose Display all the responses from RILOE II/iLO
-s, --substitute Substitute variables present in input config file
with values specified in "namevaluepairs"
-g, --get_hostinfo Get the Host information
-m, --minfwlevel Minimum firmware level
See: HP ILO 3 gives XML syntax errors with hponcfg utility or Access HP Lights-Out from remote server