Twilio cannot establish a TCP connection to your web server. The two attempts to connect to your web server were timed out. Each connection attempt has a 5 second timeout.
- firewall in your network blocking incoming TCP traffic
- network outage between Twilio and your web server
- invalid host part in the HTTP URL pointing to non-existing host or private IP address
- verify firewall configuration in your network or on the web server
- verify network connectivity to your web server
- verify the HTTP URL provided is accessible to the public Internet