It is exactly 1 month onward so it has to do with often very, very long time for the post/correos.
IF you can tell us for where and how you go there, we may tell how it can be solved
DO note-this is a very big misunderstanding often, that 1 country is what it says; ONLY in that pais. NOT for the trip home to there. Buenes viajes.
Paper passes have a long lead time as they need to be posted. They will not allow you buy a paper pass starting less than a month in advance.
Your options are to get a mobile pass or find somewhere to sell a paper pass in person.
Other members here have had passes issued in major rail stations in certain counties, I am not sure if RENFE in Spain sell them any longer though.
Depending on what country you wish to visit it may be possible to buy on arrival.
Which One Country pass you're buying? Could you provide some screenshots of the problem? Please remove any personal details.
Perhaps it's the shipping time needed, you might want to buy a mobile pass or buy the paper pass at the closest international ticket office for you.