Question about Outlook Express

my hot mail is a paid account and for the last few days when i try to send an email it says..server busy, please try again later??? what does this mean?? also is there a linit put oon how many contatcts that you send to at one time?? i was under the impression that with a paid account you could have many contatcts.. i need to be able to send multiple emails to mulitple contacts.. has this happened to any one else?? Please tell me how to fix this? Thanks you