APPC/MVS issues ATBxxxI messages to indicate the following errors:

• Incorrect syntax or other errors for the GRNAME parameter on the LUADD statement, including multiple GRNAME parameters on the same LUADD, incorrect characters in the value for GRNAME, and so on. See z/OS MVS Initialization and Tuning Reference for coding details for the GRNAME parameter.
• An attempt to dynamically change the value of the GRNAME parameter. To change the value, you must:
  1. Delete the LU by entering a SET APPC command that specifies an APPCPMxx parmlib member containing an LUDEL statement
  2. Alter the GRNAME value on an LUADD statement
  3. Add the LU by entering a SET APPC command that specifies an APPCPMxx parmlib member containing the LUADD statement.
• Incorrect level of VTAM® is installed. Unless your installation is using VTAM V4R4 or later, APPC/MVS activates the LU, but without the association with the generic resource name. Allocate requests that specify the generic resource name will fail.
• VTAM rejects the generic resource name. In this case, APPC/MVS cannot continue processing the LUADD statement, so the LU is not activated. Use the VTAM return and reason codes in message ATB066I or ATB067I to determine the cause of the error.

If necessary, see z/OS MVS System Messages, Vol 3 (ASB-BPX) for descriptions of the messages APPC/MVS issues for errors related to the use of VTAM generic resource names.

APPC/MVS also reports an error through a reason code for the Register_For_Allocates service when an APPC/MVS server uses a generic resource name explicitly on that service call, or implicitly through a side information entry. The descriptions of the Register_For_Allocates parameters Local_LU_name and Sym_dest_name, in z/OS MVS Programming: Writing Servers for APPC/MVS, contain more details about this error condition.