Error message: http POST request to 'autodiscover-s.outlook.com' failed - 456 / 457
This error indicates that the Office 365 account cannot be logged in to because the account has been locked, or its password has expired and must be changed. This error may occur following repeated failed logins, or implemented by Office 365 as a security precaution to safeguard your account.
If you are still able to log into your Office 365 account, you can validate the expiration of the admin password by executing the following PowerShell commands:
$UserCredential = Get-Credential
Connect-MsolService -Credential $UserCredential -ErrorAction Stop
If the password has expired, the following response will be displayed:
Connect-MsolService : Your password has expired. Contact your Tenant administrator to reset your password.
At line:1 char:1
+ Connect-MsolService -Credential $UserCredential -ErrorAction Stop
+ CategoryInfo : OperationStopped: (:) [Connect-MsolService], MicrosoftOnlineException
+ FullyQualifiedErrorId : 0x80048831,Microsoft.Online.Administration.Automation.ConnectMsolService
To fix this error, Log in to your Office 365 account and unlock the account, or change the expired password.