Email not going from yahoo to hotmail its bouncing

This is a known deliverability problem between external senders and Microsoft consumer mailboxes (Hotmail/Outlook.com) that must be fixed on the service side; there are no client-side settings in Outlook/Hotmail that will resolve it.

From the Microsoft side, the usual checks for Outlook.com/Hotmail accounts are:

1. Verify the Hotmail/Outlook.com mailbox is healthy
   • Make sure Microsoft cloud storage and mailbox are not full; if storage is full, messages to the account are bounced and unrecoverable. Use the mailbox storage page referenced in the Outlook.com article to confirm usage.
   • Confirm the account is not blocked due to unusual sign-in activity and unblock it if necessary using the guidance in the Outlook.com help.
2. Check for standard non‑delivery causes
   • When messages bounce, the NDR (bounce) from Microsoft typically includes a reason such as invalid address, mailbox full, server issues, or spam filtering. Review the exact error text in the bounce from Hotmail to understand whether Microsoft is rejecting as spam or for another reason.
3. If the Hotmail address can send and receive from other domains
   • If the Hotmail account can send and receive with other providers (e.g., Gmail) and only Yahoo→Hotmail is failing, the issue is almost certainly on the Yahoo side (reputation, configuration, or routing) and must be addressed by Yahoo.
4. What affected users can do
   • On the Hotmail/Outlook.com side, add the Yahoo sender to Contacts and to the Safe senders list to reduce the chance of spam filtering, as described in the Outlook.com article.
   • If the Hotmail user is new, be aware there is a temporary low sending quota until credibility is established, but this affects sending, not receiving.
5. When to escalate
   • If storage is not full, the account is not blocked, and the NDR indicates a server or spam‑filter issue on Microsoft’s side, affected Hotmail/Outlook.com users should use Outlook.com in a browser, open Help, and follow the Still need help? path to contact support, or use the Outlook.com support link in the article. Include full NDR details so support can investigate service‑side filtering.
   • Yahoo senders should open a support case with Yahoo, providing the NDR from Microsoft, so Yahoo can work with Microsoft if there is a broader interop or reputation issue.

Because this is a cross‑provider mail‑flow problem, resolution typically requires provider‑side fixes rather than any local Outlook or client configuration changes.

References:

• Can't send or receive email in Outlook.com