Tax code ZT does not appear in any G/L account item

Hi Gurus

Iam facing a proble while releasing the billing document to accounting. Following error is coming up

'Tax code ZT does not appear in any G/L account item'.

FTXP setting for the tax code appears find as it is tagged to the correct GL account, but somehow the posting is not happeing.

Can you please help me out with this as Iam stuck and the testing has stopped.

Thanks

Ruchi