This morning the EBU has announced that Azerbaijan’s neighbour country Armenia will not participate this year. The official statement did not mention any particular reason, but uttered their disappointment "We are truly disappointed by the broadcaster's decision to withdraw from this year's Eurovision Song Contest” said Jon Ola Sand (Executive Supervisor of the ESC)
The probably reason for this will be that the ongoing political conflict between Armenia and Azerbaijan could not be reduced yet. Officially there is no peace announcement between both countries, and there have been some border disputes recently. The organizers could not guarantee a 100% protection for the Armenian delegation in Baku.
This is not the first time that a country withdraws; recently Georgia has withdrawn from the 2009 contest in Moscow, as the song had a song title with a word play of the Russian president Putin. The Georgians did not want to change the title and finally they have withdrawn.