Oracle Message PGA-21011 - invalid network name length (number), valid range is number: number

ERROR	invalid network name length (number), valid range is number: number
CAUSE	The network name portion of the fully-qualified local LU name specified as the first argument to the pg4arrm program is the wrong length ().
ACTION	The valid range of lengths for the network name is given in the message text by : . Reenter the command line with a valid network name specified in the fully-qualified local LU name.