how to handle connection lost on iphone when uploading a form IPHONE

I have a form that requires users to upload information, and files. It then sends an email to me with their information. It saves their files into a folder and saved their information to the database. all upon submitting the form.

Then it redirects to a thank you page.

this is working great on desktop with no problem what so ever, however when testing this on my iphone 4 and iphone 5 i get a problem every 1 in 2 times i try.

When i click submit i get:

Safari cannot load the page because the network connection was lost

Now could this be down to big mysqli usage and doing various other things? how do i go about making this a better experience as i know websites like ebay/amazon which are much more resource heavy cope just well.