Domain Name emails have stopped working - HELP!

I recently transferred my domain name from GoDaddy to SquareSpace and as soon as I did that I stopped receiving my domain name emails. This is the error email I get when I try sending a test email to my domain name email: 

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From: [Edited: "Personal Information"]

Permanent Error

     This is an automatically generated Delivery Status Notification.      

Delivery to the following recipients failed permanently:

  * [Edited: "Personal Information"]

Reason: Permanent Error

Reporting-MTA: dns; resqmta-ch2-04v.sys.comcast.net [69.252.207.36]
Received-From-MTA: dns; resomta-ch2-09v.sys.comcast.net [69.252.207.105]
Arrival-Date: Tue, 20 Apr 2021 02:42:02 +0000


Final-recipient: rfc822; [Edited: "Personal Information"]
Diagnostic-Code: smtp; 550 5.1.1 < [Edited: "Personal Information"]> Recipient not found.  <http://x.co/irbounce>

Last-attempt-Date: Tue, 20 Apr 2021 02:42:03 +0000

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Who should I be contacting to fix this? Comcast? SquareSpace? GoDaddy?

Thanks.