PowerShell refresh dataset

[GoingIncognito]

Hi.

I'm trying to use this to update a dataset in portal:

$User = "firstname.lastname@company.com"
$PW = "VerySecretivePassword"

$SecPasswd = ConvertTo-SecureString $PW -AsPlainText -Force
$myCred = New-Object System.Management.Automation.PSCredential($User,$SecPasswd)

Connect-PowerBIServiceAccount -Credential $myCred

$DataSetID = "XXXX-XXXX-XXXX-XXXX"
$WorkSpaceID = "XXXX-XXXX-XXXX-XXXX"

$RefreshDSURL = 'groups/' + $WorkSpaceID + '/datasets/' + $DataSetID + '/refreshes'
$MailFailureNotify = @{"notifyOption"="MailOnFailure"}
Invoke-PowerBIRestMethod -Url $RefreshDSURL -Method Post -Body $MailFailureNotify

But what I get back is:
Failed to get ADAL token: Unhandled Exception: System.AggregateException: One or more errors occurred. ---> Microsoft.IdentityModel.Clients.ActiveDirectory.AdalClaimChallengeException: AADSTS50076: Due to a configuration change made by your administrator, or because you moved to a new location, you must use multi-factor authentication to access [...]

Response status code does not indicate success: 400 (BadRequest)

Sure, we do use MFA but it pop-up only flashes quickly. What should I do about the ADAL token?
Thanks - a lot!