I have double citizenship, Italian + UK. I've applied for US ESTA with my Italian passport as primary and added my UK passport as 2nd citizenship. They are both valid and not expired. My request has been denied and I don't understand why. In theory there should be no problem but I can't find why it was rejected. In the past I've used a DS156 visa as a student and it has been issued without problems. Any idea if there are problems for my situation that I can't see?
EDIT: I've been at the consulate and it turns out that there was a note on my profile about the fact that I used two different passports in the past. The lady I talked to edited my file and I got the tourist visa without problems. This is the reason the ESTA was rejected.
I went to the States 2 weeks ago without any problem at the customs check.