Footer portlet broken

[jensens]

On Plone 5.2 (Python 3.6, zeocluster) I installed the collective.mailchimp module.
After the installation, 'Mailchimp' shows up in the controlpanel. So far, so good.

However, when I try to add MailChimp as a footer portlet, Only the portlet title appears. Any z3c form doesn’t show up. I ran the client in foreground mode, but I don’t see any warnings of a deprecated module that could be a dependency of the collective.mailchimp module.

Can someone point me into the direction of the actual problem? I'd be happy to contribute on solving the issue.

Originally posted by @stevenhoog in #43 (comment)