POP and IMAP, the Email Access Protocols
When you recover email messages got at your inbox from a mail server utilizing an email program (on a PC, say, or a cell phone), the server and your program (going about as the customer) have, in email's initial days, utilized the Post Office Protocol (POP) to convey.
Downloading messages to an email program is the thing that IMAP and POP offer. While POP was intended to do just that, however, IMAP gives heaps of helpful usefulness more.
POP and Its Problem with Multiple Computers or Devices
In a normal POP session, your email program will download all recently arrived messages, and afterward erase those messages from the server promptly. This technique jelly space on the server and works superbly fine, obviously—if you get to your email from just a single PC or gadget and precisely one email program.
When you attempt to take a shot at your email from more than one machine (a work area at work, a workstation at home and a telephone, for instance), POP email moves toward becoming and a noteworthy cerebral pain to oversee:
Approaching messages begin to miss from everything except one of your email programs,
message can't be downloaded effectively once more (so you swing to sending and diverting messages to yourself),
you need to re-make leads all over and
sent mail is generally just accessible on the machine from which you sent it.
This is only a short rundown of the things that have a tendency to run amiss with POP email.