Invalid text type selected for interface definition in Customizing (&1)

What causes this issue?

Invalid text type has been selected in the interface definition.

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?

Select a valid text type:
<ZK>00</>,,Special Character as Separator
<ZK>01</>,,Fixed Field Lengths
<ZK>02</>,,One Field per Line
For further information and assistance, contact your system
administrator or interface developer.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.