Im currently trying to setup a webhook on Trello, however upon webhook registration, I get back a 400 error with the following message:
{
“message”: “URL (https://tnm.etsi.org/trelloUp/webhook) not reachable. AbortError: Proxy response (503) !== 200 when HTTP Tunneling”,
“error”: “VALIDATOR_URL_NOT_REACHABLE”
}
The callback URL is valid and returning 200 for HEAD (and also GET) requests.
The SSL certificate is also valid. One point to note though is that it’s a wildcard certificate (*.etsi.org) but that should not be an issue
Note: The HTTPS HEAD call that Trello makes to validate the webhook URL is never reaching my server.
If I do the same HEAD request by myself, my service is properly responding a 200 OK response.
Is the callback URL also available to respond to the HEAD test on port 80 (HTTP) as well as 443 (HTTPS)? I tried and your website / server gave a 301 error, then forced the connection back to HTTPS.
Also, the page at that URL doesn’t seem to have any content. What happens if you add a basic HTML header with a doctype, title and dummy body content?
The server cannot serve request on HTTP port (80), per company policy. Only HTTPS/443 is allowed to go through. HTTP requests are indeed redirected to HTTPS. So I cannot setup a HTTP callback.
I’ve added some (JSON) content to the GET response, but it should have no impact as Trello is supposed to perform a HEAD request, not a GET. Anyway it does not harm.
Regarding HEAD requests, they have, per standards, no content.
You may have to speak to the sys admins at Etsi.org as they may be doing some address range blocking or connection type blocking. Do you have any other places you can try hosting your callback URL?
If this has no effect, then I can’t provide any further advice. You may have to log a dev support ticket.
yes, I’ve contacted my IT dept. as well to get some tracing done (but quite late in the evening, so not expecting results soon)
BUT ! I’ve started to see some unexpected logs arriving on my server suddenly few minutes ago 104.192.142.242 - - [08/Nov/2024:07:41:53 +0000] "HEAD /trelloUp/webhook HTTP/1.1" 200 0 "-" "Trello"
I guess som angels (whoever they are) are working on the problem
And now the webhook registration is successful \o/ (no other change on my side since last failure)
Thanks for your help SunnyApe, and thanks to the mysterious angels (Trello dev ?)
