I'm still having this issue and no could offer me help yet in the CoinsBank official thread , anyone ?
I'm not sure this will be of any help, but when I installed the CoinsBank app I had no problems at all setting the API key / linking the app to my actual CoinsBank account.
Well , I didn't type anything by hand except the password , I scanned the QR code from API key so I don't think It could be my fault anyhow ?
Is the application still working for you ? (now) ?
I don't know 100% what did I enter back then, it's quite some time since I've set it, it was shortly after Bit-X (campaign) became CoinsBank. But the app works very well since then (I've just made a test now too). I use it only for coins, I don't have a card, so I have to go to coins to actually show anything useful, but it works. I even like it more than the web interface.