Hi,
How %{reply_key} is created by discourse, for my case when outlook send reply to topic to discourse, it is getting reject by discourse. outlook report shows it sent successfully.
Server at (IP address) returned ‘400 4.4.7 Message delayed’
7/31/2018 8:39:53 PM - Server at (IP address) returned ‘451 4.4.397 Error communicating with target host. -> 421 4.2.1 Unable to connect -> SocketConnectionRefused: Socket error code 10061’