Hi Bob,
I had been using both my phone and my iPad and trying the app and cp.pt web site. I was selecting the Lisboa Rossio train station as my destination. A number of train options were displayed, but no buttons were available to make a selection. There was no error message stating that no tickets were available for that date. I also tried Lisboa Oriente on my iPad and it had the same result.
Today I used my laptop and had the same results with Lisboa Rossio filter. Then I tried Lisboa Oriente. I finally saw a button to purchase. I think it was a combination of the iPad/Phone not showing the purchase button and even the web site not showing that Lisboa Rossio was not a real option -- at least for that date. (Per Google search, it was not an allowable option from Faro.)
We chose Oriente and have purchased our tickets. The seats were defaulted, but they allowed me to make a change prior to purchase. I so seldom use my laptop. I certainly won't be bringing my laptop on vacation. So, I have a tendency to do everything on my phone or iPad. What get's crazy is that Rail Nija had the Rossio destination as an allowable journey and was going to allow me to buy our tickets several months ago. I had heard to stay far away from Rail Nija and I am glad that I heeded that warning. The trip cost only 65 Euros. Rail Nija forces a USD purchase only and was going to charge $204!
Thanks for your help!