Hi @Kareem Culbertson,
Welcome to the Microsoft Q&A platform!
According to your description,you've done a good job checking the initial steps. The issue could potentially be on either end, but let's go through a couple more troubleshooting steps to narrow it down:
- Make sure the forwarded emails are not ending up in the spam or junk folder of the second inbox.
- Ensure that the second inbox isn't full and can accept new emails.
- Sometimes forwarding can be delayed. You might want to test by sending a few emails to see if they eventually arrive.
- If you are using an email client like Outlook, make sure there are no filters or rules within the client that might be interfering with the forwarding.
- If possible, add the sender's email address to the safe sender list in both inboxes.
Please feel free to contact me if you have any queries.
Best,
Jake Zhang