I have a couple of gmail email addresses. One main address, and a few others. I pull the mail from the other email addresses to the main address via gmails "get email from other email address via Pop3" option. This has always worked for me. (And still does)

Today, I tried to do the same for my seven year old son. (Because I want to start learning him how to use email). I also created one main email address and a second one. The main email address is on the family domain extension which is coupled with Google apps (so it works like gmail basically). The second email is a "true" gmail.com address. The Pop3 and imap option has been enabled on both email addresses.

Now, when I try to set it up like so that the mail of the @gmail.com address is fetched to the main address, it doesn't work. I keep on getting the error that the pop3 password is wrong, but it isn't. I can login to the webmail app with the same password no problem. It's the same password on both email accounts even.

I'm at a loss here. Anybody knows what's going on?