11206: HTTP protocol violation

There was an error speaking HTTP to the target URL.

• Server misconfiguration
• Network disruption
• Making HTTP connections to an HTTPS port
• There is an invalid symbol in the TwiML Cookie

• Verify your web server is serving valid HTTP for the URL
• Verify the network connection to your server is stable
• Verify the URL is not directing you to an SSL port
• Remove the following characters from the TwiML Cookies: '\t', '\r', '\n', '\v', '\f'
• TwiML cookies cannot have an empty name