What is what does the white check mark mean on messenger?

The white check mark on Messenger indicates that your message has been delivered to the recipient's device. However, it does not mean that the recipient has read the message yet. If the checkmark turns blue, it signifies that the recipient has read the message. If the message remains undelivered, a gray circle with a white check mark appears. If the recipient is not reachable, there will be an exclamation mark inside the circle indicating a failed delivery. Keep in mind that turning off read receipts in chat settings or having an unstable internet connection can also affect the delivery and read status of messages.