On your listing form in Postage > Postage Method, do you by chance have Courier: Oversized item selected?
Then, use the drop down arrow to bring up the small menu and de select Courier and select, Standard postage: small to medium items.
Below this, you shoud see Domestic Postage, click on + Add primary service , and a whole list of services will appear.
The above is for a laptop / PC, sorry I don't use the app where it may be a different method.
@rerogers0180
