How to turn off end-to-end encryption on Messenger
End-to-end encryption is now available on the Messenger app for both phones and computers. End-to-end encryption is a security layer that makes chat content safer, allowing only the sender and recipient to read the messages, and requires a security code when logging in from an unfamiliar device. This can lead to the loss of Messenger messages. If you don't need such a high level of security on your own device, you can disable Messenger's end-to-end encryption.
After disabling end-to-end encryption on Messenger, you can more easily review your message history, back it up, and access it across multiple devices.
However, please note that the message content will no longer be protected by this encryption layer, meaning that others can read the message content if they have access to your Messenger account.