Magento blank alert in checkout step 1 (save billing)

Question

ver :- Magento 1.9

file :- /app/code/core/Mage/Checkout/Model/Type/Onepage.php

I am getting blank alert box at checkout 1st step.

ajax :- "/checkout/onepage/saveBilling/" Returns {"error":-1,"message":""}

$customerErrors = $customerForm->validateData($customerData);

(line no. 383, function _validateCustomerData)

returns

Array ( [0] => )

This is happening with users having work email address only, with @gmail.com users every thing is working fine.

Answer 1

For me the issue was some of the default shipping methods, i disabled UPS/USPS shipping methods (System> Configuration>Shipping Methods) and it works.