Error Code 19 - ConnectionFailed

Overview

Error Code 19 (connectionFailed) indicates that the Softdrive client is unable to establish or maintain the required network communication with the remote computer. This issue is almost always caused by firewall, EDR, or network filtering rules.

Softdrive relies on both TCP and UDP to establish and maintain a session. If UDP traffic is blocked, filtered, or heavily degraded, the connection will fail.

Common Causes

Error Code 19 is usually triggered by one or more of the following:

• Firewall or EDR blocking UDP traffic
• Network security software (Zscaler, endpoint protection, VPNs) interfering with real-time traffic
• Extreme packet loss or unstable network conditions (often preceded by Error Code 11)
• UDP traffic not flowing bidirectionally between the client and server

Troubleshoot

Required Network Ports

Please confirm that the following ports are open and allowed in both directions on all firewalls, EDRs, and network security tools between the client machine and the remote machine.

TCP (Control & Session Setup)

UDP / SRTP (Streaming & Real-Time Data)

Important:
UDP traffic must be allowed both ways. Allowing outbound UDP only is not sufficient.

For more information, see Firewall Ports Configuration and the Softstream network diagram.

What to Check on the Client Machine

• Windows Firewall allows the required TCP and UDP ports
• EDR / endpoint security software allows Softdrive UDP traffic
• VPN or network filtering software is disabled for testing
• If using Zscaler or similar tools:
  • UDP traffic is not intercepted or dropped
  • Softdrive ports are explicitly whitelisted

What to Check on the Server Machine

• Incoming UDP allowed on ports 9250–9254
• Outgoing UDP allowed on ports 58000–59000
• No network policies blocking SRTP traffic

Advanced Troubleshooting

For deeper investigation, Wireshark can be used to validate UDP traffic flow.

• On the server:
  • UDP packets received from the client IP
  • UDP packets sent back to the client IP
• On the client:
  • UDP packets received from the server IP
  • UDP packets sent back to the server IP

If UDP packets are only flowing in one direction—or not at all—the issue is almost certainly a firewall, EDR, or network filtering problem.

Summary

• Error Code 19 is not usually a TCP failure
• It is almost always caused by blocked or disrupted UDP communication
• Confirming required ports and bidirectional UDP flow resolves the issue in most cases