Message Not Posted Error

Whenever my sister tries to post a new message or topic, it would show an error saying the message cannot be posted from this IP address. When I try it with my account, it has absolutely no problem and the messages post perfectly.

The error is like this. I am absolutely sure that 40 messages were not posted within a 24 hour time period. This message keeps coming up on my sister's account, but it doesn't come up on my account. Can someone please help me with this problem?

Is your sister newbie or groupbie? I don't exact remember where I read that, but I think there was a rule limiting both of those groups from posting too many posts in a day.

Yeah,
Must be to do with the rank your sister is in