erro 500 field required

[shumy300]

Hi, I use prestashop version 1.7 and I have problems when active mandatory fields.
for example, if "address2" or "other" or "dni" is active from clients -> addresses, I'm about 500 errors. By enabling debug mode and error messages, I only see a white page.
What could it be?

[Simonas Invertus]

White page is a 500 error. If turning on debug mode doesn't show you an error message and the page is still white, you have to look in to server error logs.

We can help you only if you can present us an error message. 

[El Patron]

make sure to see your hosting error log.  Not all things (controlled by server) will display on fo for security reasons.  

[shumy300]

the server side error page is empty 

[shumy300]

ok found error log.
Here's what you've been doing since I've made a mandatory field (eg "other") and I click on "Buy Now" on the order page.

[27-Oct-2017 11:56:09 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 326
[27-Oct-2017 11:56:20 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 695
[27-Oct-2017 11:56:22 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 368
[27-Oct-2017 11:56:24 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 236
[27-Oct-2017 11:56:33 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 329
[27-Oct-2017 11:56:34 Europe/Rome] PHP Notice:  Undefined index: id_cms in /home/site/public_html/vendor/prestashop/smarty/sysplugins/smarty_internal_templatebase.php(157) : eval()'d code on line 329