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NOTESunityml-agentsdebuggingnetworkingfirewall
Unity ML-Agents - Port 5004 Connection Error Fix
August 31, 2020•Updated 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.