To unblock if someone hits this issue.
If the user has Tier-1 in the MGMT NSX-T with the name "reg-a-m01-lb01-t1-gw01" and interface IP X, user can provide the IP X in the vRSLCM deployment wizard in SDDC Manager UI, The automation will reuse that Tier-1 instead of creating a new one, but if the user does not provide the IP X instead provides another free IP address the workflow will fail at:
"Create and Configure NSX-T Data Center Tier-1 Gateway" with:-
Type: java.lang.RuntimeException
Message: Tier-1 gateway not found
In this case, the vRSLCM rollback will be available, but it will also fail and the user will be stuck.
Automation bug and wrong user input.
VCF 4.5
When the vRSLCM deployment workflow fails the user can: