Publishing a novel

My novel 'The Aviators' has been sent to Amazon, to be uploaded onto Kindle.
I have also tried to get the novel printed by Amazon in  paperback format.
That has proved to be more difficult. I have received several error messages. Nothing seems to work.

I shall just have to keep trying.
At least, it is not urgent. I will not need the paperbacks until I attend my next Science Fiction convention. The next one in my calendar, Novacon, is five months away.