I am constantly getting this error when uploading files (Play 2.6.11): SubscriptionTimeoutException: Substream Source has not been materialized in 5000 milliseconds
When I restart the application it works for some time and then I start getting this error again.
It only happens on the production system. Therefore I can not test it with Play 2.6.16 right now.
When I stop the server, I get a lot of logs for removing leftover temporary files. Like it was not able to cleanup itself while running.
Did you tried to use the file reaper? I don’t think it is related to the problem you are seeing. Could you post the complete stack trace for the error?