Access to a new email

Hi Sam, 

Thank you for reaching out and I'm sorry to hear how stressful it is to suddenly lose access to your mailbox, especially right after making a change you expected to go smoothly.  

Based on your description, the sign in issue is an expected behavior after moving your user account from the default .onmicrosoft.com domain to your new domain, so nothing is broken on your account. 

When you changed the user's domain, you also changed the account's sign-in address (the user principal name). The "we couldn't find a Microsoft account" message simply appears because the old .onmicrosoft.com address no longer works for signing in. You will now be able to get back in by signing in with your new domain address instead, for example: ******@yournewdomain.com. 

If the problem persists after trying that, please call your regional Microsoft support hotline here: Customer service phone numbers - Microsoft Support and choose Work account.  

A technical support engineer can then initiate a remote session, review backend settings, and run diagnostics. If needed, they can escalate the case to specialized engineering teams who are well-equipped to perform advanced troubleshooting and provide targeted solutions.  

As moderators, our primary goal is to provide helpful guidance and support through general troubleshooting steps. While we don’t have access to internal systems or administrative tools required to resolve account-specific or backend issues, we truly appreciate your understanding of these limitations. We genuinely hope the information we share helps point you in the right direction, and we're always here to assist as much as we can within our scope.  

I truly hope this helps you regain access to your account quickly. Even though I can't directly intervene, directing you to the correct and specialized support is the most effective help I can provide from my position.       

Thank you for your kindness and contributions to the forum.      

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