There is an issue where sending a sharing link to someone internally from within the portal is spoofed. Example. I log in to the portal and navigate out to OneDrive, pick a document, and select to share it. When the shared link is sent, a bounce back is  received internally notifying us it cant reach the intended recipient. The reason it cant reach the intended person is due to the email coming in from our own @domain.com. This is of course seen as a spoofed message and blocked by our filter. We cannot allow spoofing and have read that this is by design from MS. 

Has anyone found a solution for the above issue?

• Moved by George.Zhao CHNMicrosoft contingent staff, Moderator 41 minutes ago

you may need to whitelist the SharePoint IP from your spam filter. Below is the article contain the sharepoint latest IP.

https://support.office.com/en-gb/article/Office-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2?ui=en-US&rs=en-GB&ad=GB#BKMK_SPO

Please whilelist these Sharepoint IP and let me know if still getting non delivery report for the emails sending from sharepoint online.