I have created a gMSA like this:
New-ADServiceAccount -name Cust00000 -DNSHostName Cust00000.domain.com -PrincipalsAllowedToRetrieveManagedPassword "IIS_IUSRS" -ManagedPasswordIntervalInDays 60
And life seems to be good. However, when I run
Test-ADServiceAccount Cust00000
This is what I get:
False
WARNING: Test failed for Managed Service Account Cust00000. If standalone Managed Service Account, the account is
linked to another computer object in the Active Directory. If group Managed Service Account, either this computer does
not have permission to use the group MSA or this computer does not support all the Kerberos encryption types required
for the gMSA. See the MSA operational log for more information.
I checked event viewer -> Application and Services Logs -> Microsoft -> Windows -> Apps -> Microsoft-Windows-TWinUI/Operational but this does not appear to be correct. Where (and possibly what) is the MSA operational log?
EDIT: For the overall issue, I had tried Install-ADServiceAccount but it wasn't working. I gave up on that and finally got it working (for a gMSA named Domain\sirdank$) with Set-ADServiceAccount sirdank -PrincipalsAllowedToRetrieveManagedPassword "$env:computername$" I've also had luck with passing "Domain Computers" instead of "$env:computername$".
Having a similar issue right now. I think the log you are looking for is in Event Viewer under Microsoft/Windows/Security-Netlogon/Operational log; you might see some 9001/9002 events (Task Category of MSA) which might give you some color on what is happening.
Got this from a recent TechNet blog post that describes troubleshooting gMSA account creation/testing issues. Take a look, it might be relevant to your overall issue: https://blogs.technet.microsoft.com/joelvickery/cannot-install-service-account-the-provided-context-did-not-match-the-target/
Alternate link (it appears the same post was cross-posted with a different title): https://blogs.technet.microsoft.com/runcmd/the-rc4-removal-files-part-1-whats-in-an-error-message/