Error 0x80090303 when enabling replication

When trying to enable replication on one of my VMs in my lab setup, I encountered the following error – Hyper-V failed to authenticate the Replica server using Kerberos authentication. Error: The specified target is unknown or unreachable (0x80090303).


Needless to say, I was able to reach the replica server ( in my case), firewall settings in the replica server looked ok and I was able to TS and login to the replica server as well. As the error message indicated that the failure was encountered when authenticating the replica server, I decided to check the event viewer logs on the replica server. A couple of errors caught my eye:

(1) SPN registration failures


(2) This was followed by an error message which indicated that the authentication had failed


I was getting somewhere, so I ran the “setspn –l” command to list down the currently registered SPNs for the computer and the Hyper-V Replica entry was conspicuously absent.

I restarted the vmms service and when I re-ran the command, I could see the following (set of correct) entries


I have seen the SPN registration (b.t.w the following TechNet wiki gives more info on SPN registration failures due to intermittent network blips. There are retry semantics to ensure that the SPN registration succeeds but there could be corner cases (like my messed up lab setup) where a manual intervention may be required to make quicker progress. I also stumbled upon a SPN wiki article: which gives more info on how to manually register the SPN. I didn’t require the info today, but it’s a good read nevertheless.

After fixing the replica server, the enable replication call went through as expected. Back to work…

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