When trying to sync CiviCRM contacts to Mailchimp or updating CiviCRM from Mailchimp, the buttons "Sync contacts" don't show up on both screens: "Mailchimp Pull Sync" and "Mailchimp Push Sync".
I've got installed CiviCRM 5.21.1 and I've tested it with Mailchimp CiviCRM extension versions 2.0 and 2.0.1. Any help will be very much appreciated.