Hello, @IniobongNkanga-8038,
Welcome to the Microsoft Q&A platform!
According to your description, there's a misconfiguration issue resulting from the transition of your email hosting provider.
The email issue might be due to DNS propagation delays or cached DNS records. When you change your email hosting provider, it can take some time for the DNS changes to fully propagate, causing emails to be routed to the old server temporarily. To resolve this, check the DNS settings for your domain and ensure that the MX records are correctly pointing to one.com. Additionally, clear the DNS cache on your email client and server. Make sure to verify your SPF, DKIM, and DMARC records to prevent delivery issues.
Another possibility is that Microsoft's servers might still have cached records pointing to the old mailbox. Contact Microsoft support to ensure that all records for your old domain have been removed from their servers. Also, verify that there are no forwarding rules set up on your old Microsoft-hosted mailbox that might be causing emails to be redirected incorrectly. Ensure there are no old email client configurations pointing to the former Microsoft server. Check Junk or Spam folders to confirm emails aren't being mistakenly flagged.
Should you need more help on this, you can feel free to post back.
If the answer is helpful, please click on “Accept answer” as it could help other members of the Microsoft Q&A community who have similar questions and are looking for solutions.
Thank you for your support and understanding.
Best Wishes,
Alex Zhang