Try changing the input port to something higher than 1024. The lower port requires the graylog service to be running as root, which might be the cause the failed input.
See the following for explanation and work around using iptables: https://groups.google.com/forum/m/#!topic/graylog2/5iLepNboyOI -- You received this message because you are subscribed to the Google Groups "Graylog Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to graylog2+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/graylog2/5b83ad30-2d58-471d-b8e6-1d1a3c34507c%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
