Does your CG Envelope look like the following picture?
Image 1. Sample CG Envelope problem.
If so, you will want to start by checking two things in your Weight & Balance setup:
1. Please be sure you entered a Moment value in the 'Empty Aircraft' section on the Weight & Balance setup page. Most setup values are Arms (in.), but this particular line requires a Moment (in-lb.) value.
2. The other possibility that could cause this problem is that the the Pilot's Operating Handbook (POH) sometimes shows empty moment divided by 100 or 1,000, to keep the numbers smaller (this just simplifies viewing and working with the numbers). You may need to multiply the moment value of the POH by 100 or even 1000. If you know the Arm for this value, you can simply multiply the Arm by the Weight to get the Moment (Arm x Weight = Moment).
Also, if you are using a Fuel Moment table, be sure to enter the values in Moments rather than Arms.
Image 2. Be sure you are using an Empty Aircraft Moment and not an Arm.
Please see the Weight and Balance in ForeFlight Mobile guide (also available within ForeFlight Mobile under Documents > Catalog > ForeFlight in the iPad) for more details.
NOTE: Any time you see a value as "in-lb", the value is a Moment. If the value is simply stated as "in", then it is an Arm.