If initializing the SAML2 plugin fails for some reason then the message saying that probably won't be seen unless debugging is enabled because it logs at DEBUG level. The metadata error is interesting but not as clear as the second message.

[Wed Aug 26 13:05:12.865381 2015] [:error] [pid 29476] 2015-08-26 13:05:12 (server.c/:760) Failed to load metadata from /var/lib/ipsilon/saml2/metadata.xml.
[Wed Aug 26 13:05:12.866184 2015] [:error] [pid 29476] [26/Aug/2015:13:05:12] DEBUG(ipsilon/providers/saml2idp.py:365 IdpProvider.init_idp()): Failed to init SAML2 provider: Error('failed to create object',)