Maintain Validation Rule

Hello ,

I want to create a validation rule that indicates that when we enter certain company codes in the creation of the project, the project can not be created.

It gives the message

'Creation of the project for the company code is not possible'

In the prerequisite i indicated

PROJ-VBUKR <> CC OR PROJ-VBUKR <> CC

In the check

PROJ-VBUKR = CC OR PROJ-VBUKR = CC

When creating the project , he let me to create the project.

Can anybody tell me what i am doing wrong?

Davy