Wow, never seen anything like this. When did it happen? Have you provided an API key? or you weren't able to get to the options screen?

I cannot get to the options screen to add the API key.
Previously I had CMandrill working just fine. But with Heartbleed I had to change my API key so I tried that today and was greeted by the blank page.

Isn't it the same error message as Petr's in this thread?
https://compojoom.com/forum/116-mandrill-for-joomla/18401-back-end-page-will-not-load
( ! ) Fatal error: Cannot use object of type stdClass as array in [........]/libraries/cmandrill/query/query.php on line 236
That looks identical.

Let us do an experiment. Maybe the issue is the old api key.
Go to your database and navigate to #__extensions. Find the com_cmandrill entry and under parameters you'll see where we store the api key. Replace it with your new one and check the backend. If that doesn't fix it I'll have to have a look myself.

Actually try to go to this url once you are logged in into the backend:
http://your-site.com/index.php?option=com_config&view=component&component=com_cmandrill

This should open the component config page.

Hi Daniel,

Thanks for the help. But I get a 404 error when I go to that URL.
http://nucleus-soundlab.com/index.php?option=com_config&view=component&component=com_cmandrill

I think perhaps you meant:
http://nucleus-soundlab.com/administrator/index.php?option=com_config&view=component&component=com_cmandrill
That does indeed take me to the backend options page. I changed my API key and saved.

Here is the only really weird thing. Upon save/closeing the page my browser starts infinitely reloading it - like its in a loop of some kind... If I just choose 'save' then it seems to be fine.
I just tested the plugin and it seems to be sending through Mandrill ok again. But I still cannot reach the backend page normally. Do you want to have a look? BTW I did also contact my shared hosting at Bigscoots.com and they were unable to find any misconfigurations.

Okay, can you give me credentials to your site. Send them to daniel@compojoom.com