There are instances where some winning carriers (the carrier you're taking your Sideline number to) mistake the origin of the number, and believe the phone number to be a landline. This may cause a delay in your port request.
Please keep in mind that limitations on the port out always fall on the winning carrier's side. If you experience any errors in the port out process, please contact the desired winning carrier to see where the problem lies. Sideline will never block or place a hold on your port out request.