The he Nginx process would serve a 502 error for different reasons, so in itself, this message is not very useful. You may get 502 errors for an exception in your application, for an internal API call that causes an exception, but also if a request isn't replied to within the prescribed limits. The latter seems likely in your case, as your 502 errors are randomly received. You should investigate your app's response times.
It may prove worthwhile checking your app's handlers, and trying to reliably reproduce the error by calling the endpoints that are most likely to have caused the error. All this is above the scope of this discussion group, in fact off-topic. You should post such questions to StackOverflow <https://stackoverflow.com/questions/tagged/google-app-engine>, or other similar forums. This forum meant for general discussion of the platform and its services. By contrast, in StackOverflow <https://stackoverflow.com/questions/tagged/google-app-engine>, you get with experienced programmers, who are happy to help. -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-appengine. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/5ccba57a-3c74-4572-910e-9a431fd9e281%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
