Warning: Illegal string offset | Warning: Cannot modify header information

Hey guys,

after registering a new blog on my multisite installation, i receive the following message (only on first time) if i save a post or page:

Warning: Illegal string offset 'email' in /mypath/wp-content/plugins/mailchimp-sync/helpers.php on line 170

Warning: Cannot modify header information - headers already sent by (output started at /mypath/wp-content/plugins/mailchimp-sync/helpers.php:170) in /mypath/wp-admin/post.php on line 235

Warning: Cannot modify header information - headers already sent by (output started at /mypath/wp-content/plugins/mailchimp-sync/helpers.php:170) in /mypath/wp-includes/pluggable.php on line 1196

By the way, how can i add a mailchimp form in my footer? is there a shortcode? :slight_smile:

Thanks in advance!

Best,
David