At some point in the last few days, AJAX posts generated from iPhone posted to my Heroku app seem to be being rejected by Cloudflare. I’m getting a 400 error: Failed to load resource: the server responded with a status of 400 ()
This does NOT happen on desktop - only iPhone, from both Safari and Chrome browsers. I don’t have Android to test.
This post does NOT make it to the Heroku server. It’s rejected at Cloudflare and the response below is returned to the browser. There is literally zero useful information.
Please help - our app is effectively down, and there’s nobody to call at Cloudflare! Cloudflare response below:
This is almost certainly being returned from the origin or something on the Heroku network. There are a number of documented instances on the Heroku site that cause cause a 400 error.
If there’s nothing there you may want to open a support ticket this the redacted bits included, there’s not enough info there to hazard a guess but the odds it is an origin issue are still extremely high.
@cs-cf - yes, I see the page load in the logs, but the form submit does not show up at all. In the browser, there are no CORS errors (and usually browsers are not shy about displaying CORS errors). It’s like the request hits Cloudflare and gets rejected for some reason and fails silently. I found this on the Cloudflare site, which sounds about right, but I don’t see anything to indicate the request is malformed (works from desktop/Chrome):
400 Bad Request (RFC7231)
Server cannot or will not process the request due to something that is perceived to be a client error (e.g., malformed request syntax, invalid request message framing, or deceptive request routing).