Issue with Sending an email to Outlook distribution list from SAP

Hi,

I am trying to send an email to outlook distribution list from SAP(SBWP). it goes to SOST. i checked it in SOST, it successfully sent and transmitted.

but i dont receive the email in the outlook.

but to same Outlook distribution list i am able to send mail from outlook.

any idea what may be the issue. do we need to check with Basis team.