Hi Binh,
You may take a look at this thread in Stack Overflow <https://stackoverflow.com/questions/42255161/ssl-certificate-on-google-app-engine-not-working-properly> which seems to be similar to your issue. If the issue persists, I recommend to open a report in the Issue Tracker <https://cloud.google.com/support/docs/issue-trackers> for further investigation. -- 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/4e442877-65e8-45d4-b3e1-446a355c58de%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
