I'm not sure if this will work or if it's the correct solution, but I once ran into the same problem and this worked for me:
Before you execute the start-node-agent command, run the login command
asadmin login --host <as1> --port <as1'sadminport>
and run start-node-agent.
(I assume you created the second nodeagent pointing to as1..create-node-agent --host as1...)
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