Help: Domain Validation Failed

I have a windows server 2016 running RDS. The IIS version is 10

I had issue with the config check. At first, I was getting extensionless errror, so I added web.config below.

mimeMap fileExtension="." mimeType=“text/plain” />

Now, I if I go from the server, it’s fine. But if I try to access the configcheck from any other computers, I get 404 error.

HTTP will give 404 error
HTTPS is a success (Extensionless File Config Test - OK)

What am I missing on the IIS settings? Everything is default

This is the error that I got:
Validation of the required challenges did not complete successfully. Domain validation failed:
Invalid response from []: "\r\n<html xmlns=“http” Forbidden urn:ietf:params:acme:error:unauthorized


Hi, If the configcheck URL resolves internally for you but returns a 404 when you try it externally then the name is not resolving to the server that you think it is. The common reason for this would be your router forwarding port 80 traffic to some other server (not the one running Certify).

For http validation to work you must be able to browse to your webserver via http (port 80) on the public internet (e.g. from your phone data, not corporate wifi). By default Certify will start a temporary http challenge response service on port 80, in front of IIS, so the actual IIS configuration is normally irrelevant and it’s really firewall/port forwarding issues that are the likely problem.

If http validation is not possible due to firewall constraints etc you will need to use DNS validation instead of http validation.

Thanks. Port 80 was indeed to another server. Completely overlooked the firewall rule.

1 Like