My newest Magento customer is using the no longer supported Ultimento theme. Digging into the site I noticed that there were dozens of errors in var/report all pointing to the Ultimento Login With Facebook feature.
I tested it with my Facebook account and we got off to a good start, validating my FB login. However, it soon errored out and blew up the Magento site, likely while creating the Magento credentials.
The report in var/report is:
a:5:{i:0;s:32:”Service temporarily unavailable.”;i:1;s:938:”#0 /home/xxx/public_html/app/code/local/Mage/Facebookconnect/controllers/Customer/AccountController.php(23): Mage_Facebookconnect_Model_Client->getAccessToken(NULL)
My fix was to update app/code/local/Mage/Facebookconnect/Model/Client.php on line 44:
replacing ->setParameterPost($params);
with ->setRawData($params);
All set! Let me know how it goes.