DCERPC_NCA_S_FAULT_INVALID_TAG used to map to NT_STATUS_RPC_ENUM_VALUE_OUT_OF_RANGE, but commit 1eef70872930fa4f9d3dedd23476b34cae638428 changed it to NT_STATUS_RPC_PROCNUM_OUT_OF_RANGE. As a result 'net rpc join' against an NT4 domain doesn't have the required fallback based on NT_STATUS_RPC_ENUM_VALUE_OUT_OF_RANGE.
Created attachment 12960 [details] Patch for v4-6-test
Created attachment 12961 [details] Patch for v4-5-test
Created attachment 12962 [details] Patch for v4-4-test
Reassigning to Karolin for inclusion in 4.4, 4.5 and 4.6.
(In reply to Ralph Böhme from comment #4) Pushed to autobuild-v4-{6,5,4}-test.
(In reply to Karolin Seeger from comment #5) Pushed to all branches. Closing out bug report. Thanks!