Fix custom certificate preview error

plugin/customcertificate/src/print_certificate.php

@@ -177,6 +177,10 @@ foreach ($userList as $userInfo) {
     $htmlText .= '</tr>';
     $htmlText .= '</table>';
 
+    $myContentHtml = $infoCertificate['content_course'];
+    $myContentHtml = str_replace(chr(13).chr(10).chr(13).chr(10), chr(13).chr(10), $myContentHtml);
+
+    if (!empty($courseCode)) {
         $allUserInfo = DocumentManager::get_all_info_to_certificate(
             $studentId,
             $courseCode,
@@ -184,8 +188,6 @@ foreach ($userList as $userInfo) {
             false
         );
 
-    $myContentHtml = $infoCertificate['content_course'];
-    $myContentHtml = str_replace(chr(13).chr(10).chr(13).chr(10), chr(13).chr(10), $myContentHtml);
         $infoToBeReplacedInContentHtml = $allUserInfo[0];
         $infoToReplaceInContentHtml = $allUserInfo[1];
         $myContentHtml = str_replace(
@@ -193,6 +195,7 @@ foreach ($userList as $userInfo) {
             $infoToReplaceInContentHtml,
             $myContentHtml
         );
+    }
 
     $startDate = '';
     $endDate = '';