There are result set pending from the query:
mysqli_multi_query($connection,$query);
You need to use/store result before you can proceed with next query after: Since you look like you don't really care about the first result set, do this after the multi query..
do
{
$result = mysqli_store_result($connection);
mysqli_free_result($result);
}while(mysqli_next_result());
Another alternative is to close the connection and starts it again..
mysqli_close($connection);
$connection = mysqli_connect("localhost","username","password","tbl_msgs");
It all depends on your requirements.