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NOTESunityml-agentsdebuggingnetworkingfirewall

Unity ML-Agents - Port 5004 Connection Error Fix

August 31, 2020Updated Feb 17, 2026

Error: Unable to connect to trainer on port 5004 using API version 1.0.0. Performing inference instead.

Try disabling Windows Firewall. The firewall may be blocking port 5004.