Mailchimp / Cron Issue / Webserver Configuration

Just wanted to post this incase anyone else was having issues with not being able to drag in lists after installing and then flushing cache/following all steps.

My Cron also stopped working and my error logs gave me the following errors;

* Premature end of script headers
* mod_fcgid: read data timeout in 45 seconds

Figured it was something to do with memory/php settings as there are multiple sites on this particular server, all with different PHP settings and using various frameworks, and I was also getting joint error messages (of which I still am unsure why, but they have now disappeared).

All I did was change the following in my PHP settings:

memory_limit = "600M"
max_execution_time = "3600"
max_input_time = "3600"

Then flushed / cleared cache and ran Cron. Cron worked, and lists were updated.