An issue has been identified in Reckon APS Tax 2019.0.0 where users are unable to lodge an amendment and the following error occurs:
CMN.ATO.AS.EM063 Your activity Statement cannot be lodged.
This issue is fixed Reckon APS Tax 2019.1.0. If you are already on this version and still experiencing this issue, you will need to delete and recreate the return. Please refer to KA-01884 for instructions on how to create Amended Activity Statements.