Cs-Cart 4.3.3 Error Oops, Something Went Wrong (Forbidden). Please Try Again.

I have installed CS-Cart 4.3.3 (fresh install) and when I go to visual editor to change the logo I can't save any modified theme. I get instead this message:



Error Oops, something went wrong (Forbidden). Please try again.



Any idea??



cheers

Please check server error logs or contact CS-Cart support team