Front office and Backoffice orders are not working

[Shwetab55]

Hi,

I'm using Prestashop v1.7.6.5 and PHP v7.1

Can't create orders from Backoffice and Frontend showing 500 error.

In apache log following error is shown:
 AH01071: Got error 'PHP message: PHP Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/controllers/admin/AdminCartsController.php:494) in /var/www/html/classes/controller/AdminController.php on line 1909\n'

and in console log, for backoffice following errors are shown:
Uncaught TypeError: Cannot read property 'result' of null
Uncaught TypeError: Cannot read property 'found' of null
 

Thanks.

[Razi]

Hello,
Is this fresh installation? or you make any change in files.

Kindly also check the files and folder permissions

[Shwetab55]

Hello, 

I have made some changes in override files and some modules also have override files.

Thanks

[Razi]

If you have Backoffice access then check by Disable all overrides option.

[Shwetab55]

I have disabled all override, yet no luck.

Thanks