429 seems like rate limitation. As I read how this is documented, this is something the app should try to solve and not you. The 429 indicate how long to wait before trying again, currently which the app blatantly ignores. I can try to account for this in a new version, but unfortunately I am on holiday so you have to wait a bit before I can look at this. Meanwhile, if you are impatient, you are welcome to download the source code from github and try a fix on your own, which I would be more than happy to include 
Otherwise, a fix may occur no earlier than in 2-3 weeks time.
