Host Key Verification Strategy: Manually Trusted key verification strategy

When launching ssh-agent, I get the following error (full output in attached file):

ERROR: Connection terminated
java.io.EOFException
at java.io.ObjectInputStream$PeekInputStream.readFully(ObjectInputStream.java:2638)
at java.io.ObjectInputStream$BlockDataInputStream.readShort(ObjectInputStream.java:3113)
at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:853)
at java.io.ObjectInputStream.<init>(ObjectInputStream.java:349)
at hudson.remoting.ObjectInputStreamEx.<init>(ObjectInputStreamEx.java:48)
at hudson.remoting.AbstractSynchronousByteArrayCommandTransport.read(AbstractSynchronousByteArrayCommandTransport.java:34)
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:59)
Caused: java.io.IOException: Unexpected termination of the channel
at hudson.remoting.SynchronousCommandTransport$ReaderThread.run(SynchronousCommandTransport.java:73)