ELI5: Explain Like I'm 5

Communications server

A communications server is like a big mailbox that stores different kinds of messages and sends them from one person to another. It helps people in different places to talk to each other. When someone sends a message, like a text or an email, the communications server stores it and then sends it to the person who should receive it. At the same time, it makes sure that only the intended person can read the message.
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