I've had a Yamaha RX-A2030 using Spotify Connect for almost a year now without a problem. About two months ago I also got a Yamaha RX-A830. This worked as well.
I am controlling Spotify Connect from my IPod Touch and my Sony Experia Z1 Compact.
Approximately a month ago my problems started. Suddenly Spotify Connect didn't work.
My receivers are recognised by Spotify but when selecting any of the receivers the speaker icon is just flashing but will never go green.
When scanning the community I found several people having similar problems. I've tried all possible solutions - restarting, changing password, uninstalling, logging out, restored receivers to factory settings... No luck.
Then I found this post and tried to connect with my daughter's account. Voila! It worked.
So my conclusion is the same as Antonycml's. There is a problem with my account.
Is there anyone out there or at Spotify that can help me to fix this problem?