Checkout page Email signup to Mailer Lite

Hi there, I am trying to send the customers that sign up to my mailing list at checkout to MAILER LITE. Is there any way to do this automatically?

I tried setting up Mail chimp, Zapier from there to Mailer Lite, but for some Mailer Lite is not receiving the contacts. So I was wondering if there is an easier way to send contacts from Squarespace to Mailer Lite?

Thank you!