Problem with bounced and sendingservice

Hello,

I Have a little problem, when mailpoet send a email or newsletter, the receiver have an information that “the sender of the email could not be confirmed, official email sender : [email protected]”
On my DNS of IONOS services I Put: CNAME – mailpoet1._domainkey.www.xxx.com – dkim1.sendingservice.net
But look it’s not enough,

Can you help me!!
Thanks