How to resolve error "Failed to load MailChimp PHP library. Please refer to the installation requirements."?
Here are some steps to troubleshoot this error according to this thread: Issue #2054037 Failed to load MailChimp PHP library. Please refer to the installation requirements. (provided by @rtome, above)


Re-read the instructions in MailChimp module's README.txt
Clear the cache
Ensure Libraries module is installed and is working properly
Ensure Mailchimp library is located at sites/all/libraries/mailchimp
Check your versions:



  MailChimp module 7.x-2.x requires MailChimp library 1.3
  MailChimp module > 7.x-3.x requires MailChimp library 2.04



If MailChimp library updated, reinstall MailChimp module