As the error message indicates a communication error and because two of three systems work fine; I would concentrate on what is the difference between the two working and the non working systems.
I would think you can rule out the BE server as such as otherwise you would have the issue with all three servers.
As pkh suggested - is there a diff in the OS and what is the exact OS
in addition:
- difference in network path
- difference in subnets
- difference in open ports
- AV config
- different logon account / security
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