What causes this issue?

You entered an interval for the horizon in the form. You are not
allowed to do this, yet the system does not stop you from doing it when
you define the form.

System Response

The system cannot execute the report. It is therefore terminated.

How to fix this error?

Change the form so that you only assign single values for the horizon.
You can do this for the entire form either by row (column), or by cell.

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

Example: Horizon displayed by column only
Column 1 Column 2
|-------------------------|-------------------------|
| Horizon from 01/01/1997 | Horizon from 01/01/1998 |
| to __________ | to _________ |
-----------------------------------------------------
| ........ | ........ |
| ........ | ........ |
| ........ | ........ |
<DS:TRAN.TRM5>Change form &V1&</>

Error message extract from SAP system. Copyright SAP SE.