Bianca on "[Plugin: Sendy Widget] "Please enter a valid email address" when using the plugin two times on the site"

Hi!
I'm using the Sendy Widget two times on my blog (one in the sidebar, and one in the footer) with the exact same settings (Header, Sendy URL, List Id). The plugin works when people want to subscribe in the sidebar, but it always people an error "Please enter a valid email address" when they want to subscribe in the footer. Any ideas would be appreciated!

https://wordpress.org/plugins/sendy-widget/