Jenkins has been unresponsive intermittently with a 504 gateway timeout error. This happened this morning and according the the logs, it looked as if it was unresponsive while it was posting to slack which is not located in AWS but on premise. Jenkins posts to slack all day so I'm not sure if that is actually related. Once it came back up (on its own) I grabbed a ThreadDump which is attached.

We seem to see these 504 gateway errors 2-3 times a week, typically in the morning.
Any help would be greatly appreciated.