Checking rule not defined correctly for bank key

What causes this issue?

You have entered countries for which the checking rules of the bank
keys have not been maintained correctly in table T005.

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 your settings using the country field checks (transaction OY17).
Only the following values are possible for the selected bank key:
BIC+key Checking rule '4' (external assignment)
SWIFT Checking rule '4' (external assignment)
Bank number Checking rule '1' (bank number)

Error message extract from SAP system. Copyright SAP SE.