Alright, so I'm in email2@gmail.com, which I just created. I want to POP from email1@gmail.com to email2@gmail.com. I go to Gear / Settings / Accounts and Import / Add a POP3 mail account you own. I type in email1@gmail.com as the address, and:
Username: email1@gmail.com
Password: <Password>
POP Server: pop.gmail.com
Port: 995
Unchecked Leave a copy of retrieved message on the server.
Checked Always use a secure connection (SSL) when retrieving mail.
Checked Label incoming messages: email1@gmail.com
Unchecked Archive incoming messages (Skip the inbox)
I receive the following error message:
Server denied POP3 access for the given username and password.
Server returned error: "[AUTH] Web login required: https://support.google.com/mail/bin/answer.py?answer=78754"
Which leads me to probably one of the most unhelpful support page I've ever read in my entire life.
Beforehand, I logged into both of the accounts and went to Gear / Settings / Forwarding and POP/IMAP and clicked Enable POP for all mail (even mail that's already been downloaded) and When messages are accessed via POP delete Gmail's copy. This made no difference. Are there password restrictions in POP? I just can't think of what else it might be.