Fields that belong to the Silverpop_PH custom object must be marked as editable in the layout.

Complete the following steps to mark the fields that belong to Silverpop_PH custom object as editable.

1. Go to Setup > Create > Objects.
2. Select the Silverpop_PH custom object.
3. Go to Page Layouts and click the Edit link.
4. Select the Send Date/Time field and click Properties to configure the access of the field in the layout.
5. Be sure that Read-Only and Required check box are cleared.