Hello there,
This problem occurs if the enterprise admin account credentials that are specified in the wizard are not unique in the Active Directory forest. Password mismatches between two or more identically named accounts in multi-domain forests can cause the wizard to fail.
Consider the following example scenario:
Contoso\admin is the enterprise admin account that's specified in the Azure Active Directory Sync tool Configuration Wizard.
Contoso\admin and Fabrikam\admin are two accounts that have the same name but that exist in different domains.
Each account has a different password.
Follow here https://learn.microsoft.com/en-us/troubleshoot/azure/active-directory/user-name-pwd-incorrect
Hope this resolves your Query !!
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