TLS is essential for protecting sensitive customer data and business-critical information. It provides encryption capabilities required by most data privacy regulations. Meanwhile, HTTPS, which indicates that a website uses the TLS/SSL protocol, is an SEO ranking factor.

However, purchasing and installing a TLS certificate is just the first step. You must also ensure users can establish a secure connection by preventing and addressing TLS errors, such as TLS handshake failure or timeouts.

A TLS handshake error prevents a browser from establishing a secure connection with a website or online service. It can be detrimental to business because hackers may intercept or manipulate sensitive data such as personal information, login credentials, and credit card numbers. The ensuing security breach could tarnish your reputation, diminish customer trust, lead to loss of business, and cause compliance issues.

So why do TLS/SSL handshake failures or timeouts occur, and how can you fix them? Let's look at the most common causes, how to address them, and how to prevent these errors proactively.

Table of Contents

1. What is a TLS handshake failure?

2. What is a TLS handshake timeout?

3. How to prevent TLS/SSL handshake errors

4. Related posts

What is a TLS handshake failure?

An "SSL handshake failed" message indicates that an error has occurred when the server and the client try to establish a secure connection.

What causes a TLS handshake failed error and how to fix it?

TLS errors have various causes, which require different fixes. The most common ones include:

Client-side causes of a TLS handshake error

• Incorrect system time: A TLS error happens when the system clock is different from the actual time. Since an SSL/TLS certificate specifies a validity time frame, a mismatch in date/time can lead to a handshake failure. The user can fix this error by correcting the system time and date.
• Browser error: A browser misconfiguration or plugin may cause an SSL/TLS handshake error. The user can switch to a different browser to find out if a TLS handshake failure is caused by the browser's configuration. If the site still fails to connect, then disable all plugins and try again.
• Man-in-the-middle (MITM) attack: Besides malicious activities, this error can occur when a connection is interrupted by a network component like a firewall. If the disruption occurs on the client side, the user may adjust their VPN or antivirus settings to address the issue.

Server-side causes of a TLS handshake error

• Protocol mismatch: A TLS handshake failure occurs when the client and the server don't mutually support a TLS version, e.g., the browser supports TLS 1.0 or TLS 1.1 while the server supports TLS 1.3. In this case, the user should upgrade their browser to work with the latest TLS version.