Diagnosis
In the chart of accounts to be posted to, no accounts are defined for the tax code you used.
Procedure
Contact your system administrator.
Define the accounts to which a tax posting is to be made with the tax code entered in Customizing for taxes on sales/purchases.
To do this, choose Maintain entries (F5).
SOLUTION:
STEP 1: Go to Transaction Code OB40 > Position and click on Transaction Key MWS and Provide Chart of Accounts
STEP 2: Enter the Tax related GL Account and SAVE.
Thanks,
Adharsh KS