Using TLS 1.1/1.0: If the application is running TLS 1.1 or TLS 1.0, this error can be caused by registering these two programs. TLS 1.2 is the correct way to select the protocol used by the application.
Disabling cryptography: If cryptography is disabled for your machine, it will prevent TLS 1.2 and fall back to TLS 1.0, which can cause an error.
Socket implementation: In some cases, a certain type of socket implementation will cause an error. In some ".NET" implementations, there is a bug that can cause this error.
Missing code: Some Entity Framework users found that a certain line of code was missing, which led to an error.
Outdated ".NET" structure: In some cases, if the ".NET" structure is disabled, this error may occur. Some tasks require the .NET framework to be updated to the latest version to work correctly.
The user is far away from the Minecraft server location: this causes the user to be temporarily disconnected from the router. This is usually associated with ASUS-branded routers and their default settings.
It can also be caused by your firewall.