Cannot set default type at form level; F.T.G. Exception is not selected

What causes this issue?

You are trying to set the output form default type at the form level.
However, this is not allowed because the checkbox for
<DS:DE.P_99B_FTGROUPEX>Form Type Group Exception</> has not been
selected. This means that the output form default type can only be set
at the group level.

System Response

The system does not let you save the changes.

How to fix this error?

Set the output form default type at the group level.

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.