Mailing a different realm?

[valodyjb]

So my friend and I started playing the game a few weeks ago, and she created her account before me so she is in a different realm (I think thats what it's referred to). Im in Taywong and I know she's somewhere else. We are now both lvl 30+ and we've been trying to send each other mail since we hit lvl 20. We both charged our accounts once so mailing is available. So I was just wondering if its an issue on our side or because we're in different realms. Also we play on the same computer ( i got better specs) not sure if having similar IP might be an issue either.
Ill attach a pic showing the error that I get and next to it is a picture of me looking her up through the compare option.