I have a newly installed Azure stack hub (full-one, not ASDK) and the external network is connected to the internet via NAT. It is version 2102 and I downloaded the 2102 tools from GitHub to do the registration.
But trying to run the registration, I get the following:
2021-06-09.22-27-51: Initializing session with privileged endpoint: 192.168.144.224. Attempt 0 of 3
2021-06-09.22-28-03: Connection to 192.168.144.224 successful
2021-06-09.22-28-03: Verifying stamp version.
2021-06-09.22-28-12: Running registration actions on build 1.2102.0.10. Cloud Id: 5938857f-3da7-4c7d-8bd1-9b426881e1e7, Deployment Id: b25765a9-32f1-47f5-b7cd-b938e96a2bf0
2021-06-09.22-28-13: Creating Azure Active Directory service principal in tenant 'c4426c0b-036f-4bfb-b2d3-5c910c5389d6' Attempt 0 of 3
2021-06-09.22-30-11: WARNING
2021-06-09.22-30-11: Creation of service principal failed:
Action plan execution failed. Error: Execution timeout
2021-06-09.22-30-11: End WARNING
2021-06-09.22-30-11: Waiting 10 seconds and trying again...
2021-06-09.22-30-21: Creating Azure Active Directory service principal in tenant 'c4426c0b-036f-4bfb-b2d3-5c910c5389d6' Attempt 1 of 3
2021-06-09.22-32-37: WARNING
2021-06-09.22-32-37: Creation of service principal failed:
Action plan execution failed. Error: Execution timeout
2021-06-09.22-32-37: End WARNING
2021-06-09.22-32-37: Waiting 10 seconds and trying again...
2021-06-09.22-32-47: Creating Azure Active Directory service principal in tenant 'c4426c0b-036f-4bfb-b2d3-5c910c5389d6' Attempt 2 of 3
2021-06-09.22-34-43: WARNING
2021-06-09.22-34-43: Creation of service principal failed:
Action plan execution failed. Error: Execution timeout
2021-06-09.22-34-43: End WARNING
2021-06-09.22-34-43: Waiting 10 seconds and trying again...
2021-06-09.22-34-53: ************************ Error ************************
2021-06-09.22-34-53: Action plan execution failed. Error: Execution timeout
2021-06-09.22-34-53: at Start-ActionPlanInstance, C:\Program Files\WindowsPowerShell\Modules\Microsoft.Azurestack.Activation\Microsoft.Azurestack.Activation.psm1: line 639
at New-AzureBridgeServicePrincipal, C:\Program Files\WindowsPowerShell\Modules\Microsoft.Azurestack.Activation\Microsoft.Azurestack.Activation.psm1: line 179
2021-06-09.22-34-53: *********************** Ending registration action during New-ServicePrincipal ***********************
Searching showed a similar error around two years ago which was resolved using a longer timeout. I checked my scripts and I had the recommended change and it does not take 30 mins for each retry to fail (more like 2 minutes) so it doesn't seem like it is really hitting that timeout. I don't think there is any firewall in the way and there is no log indicating a connection failure so I'm not sure what could be happening.