It's an ongoing problem that a couple others are having as well, but wee can't figure out what it is (because the form works 99% pf the time)
Closest we can guess is that it's a router or something causing a delay when the script does it's lookup stuff on your site (verifying the site exists, checking for recip, etc)
Some people have had luck submitting at different hours of the day as well as trying over & over & over
