Adding custom domains to your Feathr account enables you to build web pages using Feathr's tools, but host them on your own domain. It also connects your email sending domain to your Feathr email marketing campaigns, which enables more stringent privacy protections.
Wix is a website builder and DNS provider. Wix does not allow for the placement of MX records for a subdomain. When authenticating your domain with Wix, do not attempt to place MX records, as they will likely override the existing email settings for your organization's top-level domain.
Instead, please contact the Feathr Support Team at support@feathr.co if you are using Wix as your domain registrar and cannot place your DNS records. We will assist you with next steps. Feathr can make custom adjustments to your account and make MX records optional to complete domain authentication.
From the Wix FAQ:
Can I connect a business email to a subdomain?
This feature can be voted for here on the Wix support forums.
If you are working with a different DNS provider, see our help article Tips for Working with your DNS/Domain Registrar.
See our help article for Connecting a Domain to your Feathr Account.