It also happens to me sometimes.
I suggest trying to refresh the page until the shoutbox works or using pop-up.
"Even if you are 100% sure that someone is a worthless, no-good Internet troll, vandal, or worse, conduct yourself as if they are not." - Wikipedia: Please do not bite the newcomers
P.S. I disabled signature displaying A(=w=)Moo You can see mine, I can't see yours.