This is odd, I can't seem to find any "failed_to_pick_backend" error logs for that timeframe, even on expanded search. Do you have an exact timestamp of a sample error?
I also found this Google Groups <https://groups.google.com/forum/#!topic/google-appengine/c-2wMh2i5ak> and StackOverflow <https://stackoverflow.com/questions/41305122/some-502-errors-in-gcp-http-load-balancing> case that may provide solution to your issue. It discusses the possibility of either a database connection or a Load Balancer issue, among others. -- 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 google-appengine+unsubscr...@googlegroups.com. To post to this group, send email to google-appengine@googlegroups.com. 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/3dd35e10-0702-40c0-852b-24be5d21ecce%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
