When using predictive planning, I keep receiving the warning "No data was pasted."

Summary: I am testing use-cases for the predictive planning feature for forecasting/budgeting. I have set up a test data form to test predictive planning. The form has all dimensions at the bottom-level with all dimensions in the POV except for Period in the columns and entity in the rows. Every time I try to paste the prediction to the open Scenario, I receive this warning message "No data was pasted. Possible reasons include: the cells are read only, new cell values are same as existing, the columns are collapsed, or paste range extends beyond the beginning or end of the