I was having login problems a few months ago. For well over a month I wasn't able to login with droid smartphone. I kept getting a message that said something "opps that didn't go too well please try again". I de-installed Delta app and re-installed again and same problem. I gave up. Then a few days ago, after not trying for several weeks, I tried again and I was able to login with no problem. I think the problem is with Delta's app.