[Plugin: Contact Form 7] dropdown menu

Hi,

I have a problem with drop down menu in Contact Form 7 (v. 3.2.1)

I have to fit in this form 210 names our stores.
but it’s working only with 202 elements inside drop down menu.

if I add 203 elements, save this form and refresh website, I’ve got error message:
“Error 324 (net::ERR_EMPTY_RESPONSE): The server closed the connection without sending any data.”

if I delete 1 item – form start working on the website.

another problem is that if I add all 210 items and save, this form is blank in back office.

if you open – Contact/Edit – you can see this form but when you open this form is just blank page.

can’t give link for this page – it is intranet.