diff --git a/tickethelpers.py b/tickethelpers.py
index e70665b..091621a 100644
--- a/tickethelpers.py
+++ b/tickethelpers.py
@@ -295,6 +295,10 @@ def _gettitle(self, ticketnumber):
         path, ticketnumber = ticketnumber
         url = '%s%s/-/issues/' % (self.url, path)
         res = super()._gettitle(ticketnumber, url=url)
+        # Instead of responding with an HTTP 404 error, GitLab returns the sign in page
+        # if the repository is either not public or doesn't exist
+        if (res['title'] == "Sign in · GitLab"):
+            raise IndexError('Project not found')
         res['url'] = url
         res['path'] = path
         res['ticketnumber'] = ticketnumber