Translation:I am reading a book, but it is not interesting.
More or less. Since Dutch doesn't really have long vowels, just open vowels, some people used to other languages sometimes are surprised by the speed of Dutch. However, in this case, part of the speed is caused by some words being more or less swallowed, depending on the version of the speaker, which doesn't make the sentence easier to understand.
Next time you get there, if the simple present is still not accepted, report that it should. It should be accepted anyway, as Dutch doesn't have a present progressive like English, and thus it doesn't help much to limit a translation to present progressive only. However, adding more than one answer to a question has to be done manually, and it helps if you report that this one still needs to get a simple present added.