Update error code to 404

Author: duongau

articles/frontdoor/front-door-route-matching.md

@@ -57,7 +57,7 @@ This section focuses on how Front Door matches to a routing rule. The basic conc
 Azure Front Door uses the following logic to match frontend hosts:
 
 1. Determine if there are any routes with an exact match on the frontend host.
-2. If there are no exact frontend hosts match, the request get rejected and a 400: Bad Request error gets sent.
+2. If there are no exact frontend hosts match, the request get rejected and a 404: Bad Request error gets sent.
 
 The following tables show three different routing rules with frontend host and paths:
 
@@ -73,19 +73,19 @@ The following table shows the matching results for the above routing rules:
 |--|--|
 | foo.contoso.com | A, B |
 | www\.fabrikam.com | C |
-| images.fabrikam.com | Error 400: Bad Request |
+| images.fabrikam.com | Error 404: Bad Request |
 | foo.adventure-works.com | C |
-| contoso.com | Error 400: Bad Request |
-| www\.adventure-works.com | Error 400: Bad Request |
-| www\.northwindtraders.com | Error 400: Bad Request |
+| contoso.com | Error 404: Bad Request |
+| www\.adventure-works.com | Error 404: Bad Request |
+| www\.northwindtraders.com | Error 404: Bad Request |
 
 ### Path matching
 
 After Front Door determines the specific frontend host and filters for possible routing rules, Front Door then selects the routing rules based on the request path. A similar logic to frontend hosts is used to match the request path:
 
 1. Determine if there are any routing rules with an exact match to the request path.
 1. If there isn't an exact matching path, then Front Door looks for a routing rule with a wildcard path that matches.
-1. If there are no routing rules found with a matching path, then request gets rejected and a 400: Bad Request error gets set sent.
+1. If there are no routing rules found with a matching path, then request gets rejected and a 404: Bad Request error gets set sent.
 
 ::: zone pivot="front-door-standard-premium"
 
@@ -147,7 +147,7 @@ The following table shows which routing rule the incoming request gets matched t
 >
 > | Incoming request       | Matched Route |
 > |------------------------|---------------|
-> | profile.domain.com/other | None. Error 400: Bad Request |
+> | profile.domain.com/other | None. Error 404: Bad Request |
 
 ### Routing decision