diff --git a/lib/appconfig.php b/lib/appconfig.php
index 3d0d6f34..c33cbe6c 100644
--- a/lib/appconfig.php
+++ b/lib/appconfig.php
@@ -457,11 +457,27 @@ public function GetDocumentServerInternalUrl($origin = false) {
      * @return string
      */
     public function ReplaceDocumentServerUrlToInternal($url) {
+        // GetDocumentServerInternalUrl() will be the same with GetDocumentServerUrl() if internal url is not specified.
         $documentServerUrl = $this->GetDocumentServerInternalUrl();
+
         if (!empty($documentServerUrl)) {
             $from = $this->GetDocumentServerUrl();
 
+            if (!preg_match("/^https?:\/\//i", $url)){
+                // $url is not a complete url. Form it with $from
+                $parsedUrl = parse_url($from);
+
+                // $url may include VPATH. Judge it to avoid dupe.
+                // https://github.com/ONLYOFFICE/document-server-proxy/blob/master/apache/proxy-to-virtual-path.conf
+                $vpath = $parsedUrl["path"];
+                if (empty($vpath)){
+                    $vpath = "/";
+                }
+                $url = $from.preg_filter("#^$vpath#i", "", $url, 1);
+            }
+
             if (!preg_match("/^https?:\/\//i", $from)) {
+                // Frontend forbids input incomplete url, so this will never happen?
                 $parsedUrl = parse_url($url);
                 $from = $parsedUrl["scheme"] . "://" . $parsedUrl["host"] . (array_key_exists("port", $parsedUrl) ? (":" . $parsedUrl["port"]) : "") . $from;
             }
diff --git a/lib/documentservice.php b/lib/documentservice.php
index 308d1d68..cda97d99 100644
--- a/lib/documentservice.php
+++ b/lib/documentservice.php
@@ -97,7 +97,13 @@ function GetConvertedUri($document_uri, $from_extension, $to_extension, $documen
         $isEndConvert = $responceFromConvertService->EndConvert;
 
         if ($isEndConvert !== null && strtolower($isEndConvert) === "true") {
-            return $responceFromConvertService->FileUrl;
+            $fileUrl = $responceFromConvertService->FileUrl;
+            if ( !preg_match("/^https?:\/\//i", $fileUrl) ){
+                $url = parse_url($document_uri);
+                $fileUrl = $url["scheme"] . "://" . $url['host'] . (array_key_exists("port", $url) ? (":" . $url["port"]) : "") . $fileUrl ;
+            }
+
+            return $fileUrl;
         }
 
         return "";