diff --git a/relay/channel/api_request.go b/relay/channel/api_request.go
index 9540195cd..57f15bd33 100644
--- a/relay/channel/api_request.go
+++ b/relay/channel/api_request.go
@@ -98,6 +98,19 @@ func processHeaderOverride(info *common.RelayInfo, c *gin.Context) (map[string]s
 	return headerOverride, nil
 }
 
+func applyHeaderOverrideToRequest(req *http.Request, headerOverride map[string]string) {
+	if req == nil {
+		return
+	}
+	for key, value := range headerOverride {
+		req.Header.Set(key, value)
+		// set Host in req
+		if strings.EqualFold(key, "Host") {
+			req.Host = value
+		}
+	}
+}
+
 func DoApiRequest(a Adaptor, c *gin.Context, info *common.RelayInfo, requestBody io.Reader) (*http.Response, error) {
 	fullRequestURL, err := a.GetRequestURL(info)
 	if err != nil {
@@ -121,9 +134,7 @@ func DoApiRequest(a Adaptor, c *gin.Context, info *common.RelayInfo, requestBody
 	if err != nil {
 		return nil, err
 	}
-	for key, value := range headerOverride {
-		headers.Set(key, value)
-	}
+	applyHeaderOverrideToRequest(req, headerOverride)
 	resp, err := doRequest(c, req, info)
 	if err != nil {
 		return nil, fmt.Errorf("do request failed: %w", err)
@@ -156,9 +167,7 @@ func DoFormRequest(a Adaptor, c *gin.Context, info *common.RelayInfo, requestBod
 	if err != nil {
 		return nil, err
 	}
-	for key, value := range headerOverride {
-		headers.Set(key, value)
-	}
+	applyHeaderOverrideToRequest(req, headerOverride)
 	resp, err := doRequest(c, req, info)
 	if err != nil {
 		return nil, fmt.Errorf("do request failed: %w", err)