I had problems with the app, which is different than the computer. The app kept quitting at the "location" part. I also got a similar message to the pone you posted. Try using your computer. I found it way easier.
What will he need to take to immigration regarding the bangkok address? I don't think he has a piece of paper with registered address in his passport (like we do)
OK. His extension was due in Feb, but he was in Bangkok, staying with family, for a month. So he did the extension there (not sure what office). I am sure he used the family's address, where he was staying.
Now, he has traveled back to his "home" district, and is wondering what he will need when going for check in.
AMERICANS: I just got off the phone with the US Embassy in Bangkok. They informed me, that so far, they are NOT providing letters for extensions of stay for Americans because citizens are still able to fly back to the USA. :/
But to keep checking travel.state.gov for updates (located at the very top of the page)