Service response is a 502 Bad Gateway error with generic "Server Error" HTML block?
I wrote a Node service that takes parameters from a client and puts them into a SOAP request to another (3rd party) service. Lately, when a request is made to my service, the initial response is a 502 Bad Gateway error with a generic HTML block titled "Server Error" (see image). When I submit the same request a second time, the 3rd party responds with a 500 Internal Server error and a message indicating that a request has already been issued for that transaction.
Obviously the initial request made it to the 3rd party somehow, but they say that the 502 error isn't theirs and isn't logged in their system as ever having occurred.
What I'm trying to find out is if the error is somehow coming from my service because of Docker or Azure (or something else I'm not thinking of). The error is so generic that research hasn't yielded anything useful on it. Has anyone encountered this or know what it is?
It turns out that this was an error being thrown by Azure (or so we think) as the result of some faulty error-handling. Part of the response was being parsed incorrectly, which caused the app to stall. It still doesn't explain how the data still got to the other side while this was happening (or why it hit the catch block at all when there was no error in the processing), but if you see a server error returned with this HTML block, check your error-handling code and investigate Azure!