Error in determining posting key & account key &

What causes this issue?

No posting keys could be found for the account key defined in the tax
calculation procedure.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Check the following settings in taxes on sales/purchases Customizing.
To do this, choose <PF>Maintain entries</> (<PF>F5</>):
Check or correct the calculation procedure.
Check whether you have specified a valid transaction key in the tax
type used.
If it is a new transaction key, you must first define the posting
rules. Enter the transaction keys in the calculation procedure.

Error message extract from SAP system. Copyright SAP SE.