I'm getting the same exception as @stewartbryson. It doesn't seem to be related to the artifact size (I've uploaded 64 Mib successfully), but it always happens on the second artifact in releaseAssets.
at java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[na:1.8.0_111-internal] at java.util.concurrent.FutureTask.get(FutureTask.java:192) ~[na:1.8.0_111 ...
Upon failing to log into a server, you should first check if the server itself is experiencing an error. If that's the case, it could explain why you get the ...