This started impacting our Android build today as well, and we haven’t changed anything about our build config/tools recently.
It looked to me similar to this old issue from a year ago. The comments there led me to look at https://dl.google.com/android/repository/repository2-1.xml where it appears that the Android license was updated at 2019-01-18 13:05:43.965908 (yesterday). Our previous successful build was 3 days ago, so this seems potentially related.
The weird thing is that I would expect the current Docker image to still work, given the PR that resolved the previous issue which appears to accept all licenses. I wonder if something changed about the sdkmanager tool.
I started trying to work around the problem briefly, but then I found this thread. I hope this can be resolved soon.