Blank white screen - Login with admin account

When I log in to the storefront with my admin account I receive a blank white screen. For me to see the site, after admin login, I must clear the cookies.

I checked the logs, and everything is fine, no error appears.
I tried the development mode and still no error.

When I log in with a customer account to the storefront the site works fine.

I tried to check with echo where the execution reaches on specific pages. And it goes until the end of the controller. Every echo or fn_print_r displays correctly, but it never reaches the smarty files.

Has anyone faced this error before?
Any tips for me to debug it?

The version of cscart is 4.9.3.SP1

Please make sure that the used php version meets requirements for 4.9.3

The php version is correct. But still, if it wasn’t why would affect the admin users trying to login into the storefront?

There could be conflict in the code which should be examined on your server directly

Probably but it is tough to spot it. Thanks a lot for your help.

Please contact us via Help Desk on this case.