Hello Brian,Can you please share more details about the server? Because
its working fine at our end.Although preview of the attachment is
disabled by default but that has no relation with submission failure. Is
it working fine for anonymous user without attachment?
As mentioned above best approach is to use the numeric field. If server
is 6.3 onwards then there is a property (Maximum Number of Digits) to
set the maximum no. of allowed digits in numeric field that can control
the limit of entered digits.