Fix DistNetworkError

✅ Solution

DistNetworkError in PyTorch Lightning distributed tests often arises from address conflicts, specifically the EADDRINUSE error, indicating a port is already in use. To fix, specify available ports by setting the MASTER_PORT environment variable using os.environ["MASTER_PORT"] = str(find_free_port()), or configure the TCP store to find an open port automatically, mitigating address collisions during distributed initialization.