"FATAL ERROR" when trying to add member manually from MailChimp

When i try to add members manually i get the error:
Fatal error: Uncaught exception 'M2_Mailchimp_List_InvalidUnsubMember' with message 'cpnalley@gmail.com has unsubscribed, and cannot be resubscribed by you. To prevent false spam complaints, they'll need to resubscribe of their own free will.' in /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/lib/mailchimp-api/Mailchimp.php:251 Stack trace: #0 /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/lib/mailchimp-api/Mailchimp.php(226): M2_Mailchimp->castError(Array) #1 /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/lib/mailchimp-api/Mailchimp/Lists.php(743): M2_Mailchimp->call('lists/subscribe', Array) #2 /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/app/addon/mailchimp/class-ms-addon-mailchimp.php(442): M2_Mailchimp_Lists->subscribe('42fc0150f7', Array, Array, 'html', false, true) #3 /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/ap in /homepages/14/d369779940/htdocs/clickandbuilds/MedicYine/wp-content/plugins/membership/lib/mailchimp-api/Mailchimp.php on line 251

i have tried checking the mailchimp logs and it says :
[June 2, 2016 1:55 pm] [CODE:211] [EMAIL:] - This list does not have interest groups enabled
[June 2, 2016 1:50 pm] [CODE:215] [EMAIL:] - The email address "cpnalley@gmail.com" does not belong to this list

i went to mailchimp to try and figure this out but i'm getting no where. i made sure mailchimp has a working API key in my wordpress site but i don't know what else to try...