In case you are facing an "Please enter a valid email" error while signing-in (see the image below), it means that your Azure Active Directory (AAD) tenant domain has not been added to our authentication solution.
To resolve this issue, please provide the following information by Submitting a request through the Knowledgebase to our Support :
List of Azure AD custom domain names from the Azure Active Directory, which the affected AAD user belongs to:
- Main Azure AD domain - xxx.onmicrosoft.com
- Custom domain names - alternative domain names connected to the main xxx.onmicrosoft.com Azure tenant domain (e.g. contoso.com, contoso.test.com, dev.contoso.eu, etc.)
The complete list of the organization's Azure Active Directory custom domain names can be found in the Azure management portal or in the Microsoft 365 Admin Center: