diff --git a/youtube_dl/extractor/animeondemand.py b/youtube_dl/extractor/animeondemand.py
index 34c2b363ea..be032d5b42 100644
--- a/youtube_dl/extractor/animeondemand.py
+++ b/youtube_dl/extractor/animeondemand.py
@@ -85,8 +85,8 @@ def _login(self):
 
         if all(p not in response for p in ('>Logout<', 'href="/users/sign_out"')):
             error = self._search_regex(
-                r'<p class="alert alert-danger">(.+?)</p>',
-                response, 'error', default=None)
+                r'<p[^>]+\bclass=(["\'])(?:(?!\1).)*\balert\s(?:(?!\1).)*\1[^>]*>(?P<error>.+?)</p>',
+                response, 'error', default=None, group='error')
             if error:
                 raise ExtractorError('Unable to login: %s' % error, expected=True)
             raise ExtractorError('Unable to log in')