Play deploy on Heroku failed uncaught fatal error from Akka actorsystem

[Sarav Ramaswamy]

I am trying to deploy my Play/Scala 2.5.4 to Heroku (with free dyno). I am getting this error and application is not going live.

20:51:27 web.1   |  2017-08-12 20:51:27,035 [error] a.a.ActorSystemImpl - Uncaught fatal error from thread [application-akka.actor.default-dispatcher-5] shutting down ActorSystem [application]

JVM options (as per the logs):

Picked up JAVA_TOOL_OPTIONS: -Xmx350m -Xss512k -Dfile.encoding=UTF-8

Increasing memory doesn't help. Any idea why I am getting this error ? App runs fine on Mac.

[Joe Kutner]

How many threads does your application use locally?

I believe a common cause for this error is the inability to create a new thread (but that's only speculation). You may have reached the process/thread limit on a free Heroku dyno, or the JVM is unable to allocate memory for the thread stack (adjusting heap memory will not affect this, but increasing Xss may).

Also, how much physical memory does your application use locally (that is, not just heap memory).