400 The Plain HTTP Request Was Sent To HTTPS Port

A plain HTTP request is sent from a web browser, while an HTTPS port is used for secure communication.

When a plain HTTP request is attempted on a website that uses HTTPS, the browser sends a request to the server's HTTPS port. This can cause various issues, including:

• SSL/TLS handshake errors
• Error code 401: Unauthorized due to insufficient SSL certificates
• Server configuration errors that prevent HTTPS from being established

To resolve this issue, ensure that the web server's firewall or security software is configured to allow incoming connections on the specified port. Additionally, verify that the server has the necessary SSL/TLS certificates installed and enabled for secure communication.

For more information on troubleshooting plain HTTP requests sent to HTTPS ports, refer to the provided conference presentation on "Porta Est Nascetur Proin" (https://conferences.law.stanford.edu/ipsummerschool2022/2013/12/29/porta-est-nascetur-proin)

https://conferences.law.stanford.edu/ipsummerschool2022/2013/12/29/porta-est-nascetur-proin