diff --git a/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/OAuthGitFilter.java b/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/OAuthGitFilter.java
index cd8b32e..91f3b86 100644
--- a/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/OAuthGitFilter.java
+++ b/github-oauth/src/main/java/com/googlesource/gerrit/plugins/github/oauth/OAuthGitFilter.java
@@ -150,7 +150,12 @@
         gerritPassword =
             generateRandomGerritPassword(username, httpRequest, httpResponse,
                 chain);
-        httpResponse.sendRedirect(getRequestPathWithQueryString(httpRequest));
+        if (Strings.isNullOrEmpty(gerritPassword)) {
+          httpResponse.sendError(SC_FORBIDDEN,
+              "Unable to generate Gerrit password for Git Basic-Auth");
+        } else {
+          httpResponse.sendRedirect(getRequestPathWithQueryString(httpRequest));
+        }
         return;
       }