Hello Cliff
Firstly, apologies for the delay in responding here and any inconvenience this issue may have caused.
Based on the details shared, looks like the HpcNaming service on the head node could not be connected to resolve the scheduler name. Request you to double check if the communication certificate is installed correctly,
e.g. run netsh http show sslcert
to see if the communication certificate with the thumbprint in LOCAL_MACHINE\SOFTWARE\Microsoft\HPC\SSLThumbPrint is bound to port 443.
Hope this helps.
If you need further help on this, tag me in a comment.
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