Posting keys &1 and &2 are not defined for the same account type

What causes this issue?

You want to post to one account using both posting keys &v1& and &v2&.
This is only possible however, if both posting keys have been defined
for postings to the same account types. This is not the case however.

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.