Communication error with the external tax system(vertex_ms0018)

Hi All

I have installed ECC6 IDES S/W on my PC. I have activated SAP Insurance module (FS-CD). When I try to create business partner using FPP1 with US address, It is throwing error as follows:

"communication error with the external tax system(vertex_ms0018)"

I dont want to use any external Tax system like Vertex etc. because I am not calculating any taxes.

I gave correct US address with valid ZIP etc. but no use.

Please help me if any one of you has idea. How to overcome this error. How to deactivate connection to external tax system.

Your help will be greatly appreciated.

Thanks

Giri