Functions/Connect-MSOnlineAdminAccount.ps1

<#
.SYNOPSIS
    This function connects to MSOnline using admin account credentials or a MSPComplete Endpoint.
.DESCRIPTION
    This function connects to MSOnline using admin account credentials or a MSPComplete Endpoint.
    It returns whether the connection and logon was successful.
.EXAMPLE
    Connect-MSOnlineAdminAccount -Endpoint $Endpoint
.EXAMPLE
    $Endpoint | Connect-MSOnlineAdminAccount
.EXAMPLE
    Connect-MSOnlineAdminAccount -Username $username -Password $password
#>

function Connect-MSOnlineAdminAccount {
    [CmdletBinding(PositionalBinding=$false)]
    [OutputType([Bool])]
    param (
        # The username of the MSOnline account.
        [Parameter(Mandatory=$true, ParameterSetName="credential")]
        [String]$username,

        # The password of the MSOnline account.
        [Parameter(Mandatory=$true, ParameterSetName="credential")]
        [SecureString]$password,

        # The MSPComplete Endpoint.
        [Parameter(Mandatory=$true, ParameterSetName="endpoint", ValueFromPipeline=$true)]
        $endpoint
    )

    # If given endpoint, retrieve credential directly
    if ($PSCmdlet.ParameterSetName -eq "endpoint") {
        $msolCredential = $endpoint.Credential
        $username = $msolCredential.Username
    }

    # Create the MSOnline credential from the given username and password
    else {
        $msolCredential = [PSCredential]::new($username, $password)
    }

    # Logon to MSOnline
    try {
        Connect-MsolService -Credential $msolCredential -ErrorAction Stop

        # Logon was successful
        Write-Information "Connection and logon to MSOnline successful with username '$($username)'."
        return $true
    }

    # Logon was unsuccessful
    catch {
        Write-Error "Failed MSOnline account login with username '$($username)'.`r`n$($_.Exception.Message)"
        return $false
    }
}