@taotao The issue here is that DNS resolution fails for some reason, but said reason isn’t visible since it is improperly logged (the address holding the error is logged -
table: 0x5c909238 - instead of the error contents).
The error should be visible (instead of the address holding the table) in more recent versions of Kong. I advise that you upgrade to a more recent version (e.g. 1.x release family) if you can. As for which precise version of Kong this was fixed in (allowing the actual error to be visible), @Tieske can clarify (I don’t recall off the top of my head right now).
Eventually, you will have to fix the underlying error once you will have identified it (by upgrading Kong to fix the log).