Hi, 
Can you try applying " Server Network Interface" settings for this failing 
client, in order to do this, you would first need to setup the server to 
respond to the new interface setting via host file, if you do not use this 
method now.
i.e as an example, where
 IPA is your regular network
IPB is your backup network or Firewall  interface.
HOST FILE
SERVERA  IPA "10.10.10.0" 
SERVERA IPB  " 20.20.20.0"

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