z/OS Communications Server
x'3003'   RC_LU_ALL_IN_USE 


RC_LU_ALL_IN_USE  

There is no available Telnet lu for this connection.  This can be caused by several reasons.  When lunames
are inactivated, it reduces the number of available lunames that the Telnet Server can use for sessions.  If
the lunames are contained in a relatively small LUGROUP, DEFAULTLU pool, DEFAULTLUSPEC pool, etc.,
this error could occur when it appears that there are still many lunames available for the Telnet Server to use.

Are there any lunames in the INACTIVE POOL
Determine  which pool has the failing luname defined
?
Are the lunames defined in TCPIP consistent with and active in VTAM
?