Translations differ with respect to whether the messiah appear at the beginning or end of the 490 years. – Does the messiah appear after 49 years or after 483 years? The difference is due to assumptions with respect to punctuation. The original text does not have any punctuation.
Decree to restore and rebuild Jerusalem – The 490 years of Daniel 9 begin with a decree to restore and rebuild Jerusalem. Four Persian decrees are considered. Cyrus did not restore Jerusalem as national capital. Darius simply confirmed Cyrus’ edict. We have to choose between the two decrees of Artaxerxes.
Does Daniel 9 describe the same crisis as the other prophecies in Daniel? – Interpreters often assume that Daniel 9 predicts the same crisis. This article discusses the differences between the prophecies and concludes that Daniel 9 deals with Israel specifically, while the other prophecies deal with all nations.