Set up two separate LUNs on same iSCSI target for two different initiators

I'm trying to setup my iSCSI server using targetcli. Initial setup went fine and my Windows iSCSI initiator can connect to my first target / portal / LUN. Now I'm trying to setup another LUN. I want it to be separate, such that my Windows client won't even attempt to mount it and such that my Ubntu client would only mount the new LUN. So I created another target under iscsi, added a tpg and set up a new acl there and bound a iblock backstore to it. As far as I can tell, the setup is completely the same as the original target. I also added a portal to 0.0.0.0:3260, same as the original target. Now, issuing discovery (iscsiadm -m discovey -t st -p myserver) in my client Ubuntu correctly identifies both targets. However, my next step, trying to log in (iscsiadm -m node --login) fails with message 24 - iSCSI login failed due to authorization failure. * I have tried adding the credential info as suggested here with no success. * Removing the target ACL also gives me no joy. * Setting up two different ACLs within the original target as well. Anyway, at this point I'm now stuck unable to complete the second step (login). If I understand this correctly, that would also attach all LUNs on the target to my ubuntu initiator. I'm obviously missing some detail here and would appreciate any pointers. My current targetcli configuration: Each of the acls has auth userid set to same name as acl name and password set to something between 12 and 16 characters long. ACL name is in one instance the same one as suggested by the Windows iSCSI initiator, in the other, I just made up some name using same format, but different company name and initiator machine name. tpg is set such that ACL authentication takes precedence.