Error Saving Tiered Pricing Plan

We are trying to add a tiered add on to one of our plans, and unfortunately we are getting an error ("Error(s) saving plan, please correct") when we go to save the plan, but there are no errors visible on the screen for us to correct. How do we fix this.

 

Solution- Make sure the Editable Quantities box is checked under Hosted Page Settings. 

 

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