Hi Mason,
Thanks for posting in the community. We are happy to help you.
According to your description, I suggest you try the following suggestions on your end and then check again.
- Please open the InPrivate browser window, go to Outlook for Web (https://outlook.office.com/mail/), and check all emails in Inbox and Junk Email again. See if you can find the verification code email.
- Since the verification code email is from ******@sharepointonline.com, I suggest you go to add ******@sharepointonline.com as a contact in your personal account. After that, please click Send code and check again.
If the above suggestions don't help, it is likely caused by the backend. I have searched for existing service incidents and have not found any similar service incidents reported. Therefore, I suggest you report this problem to your tenant admin or IT team and have them raise a support ticket via Microsoft 365 Admin Center> Support> New service request. That support team there will have the correct channel and resources to help you investigate more and find what exactly the reason has caused this problem at the backend.
Appreciate your understanding and patience.
Sincerely,
George | Microsoft Community Moderator