How To Fix SSFCOMPOSER606 - Field "&1": Invalid type "&2" (internal ABAP)

SAP Error Message - Details

• Message type: E = Error

• Message class: SSFCOMPOSER - Smart Forms: Composer Messages

• Message number: 606

• Message text: Field "&1": Invalid type "&2" (internal ABAP)

What causes this issue?

In the form a field is used, which is no elementary field but, for
example, a structure.
Only elementary fields are allowed, that is, fields of ABAP types
C Character
N numeric Text
D Date: YYYYMMDD
T Time: HHMMSS
X heXadecimal
I Integer
s 2 Byte Integer
b 1 Byte Integer
P Packed
F Float
g String
y X-String

System Response

Form printing is terminated.

How to fix this error?

Change the fields used in the form to elementary fields.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.