NullReferenceException when running New-SPSite

Question

I'm running the following PowerShell script on my SharePoint server to create a new host-header site collection and a tenant admin site:

Add-PSSnapin microsoft.sharepoint.powershell -ea SilentlyContinue

$featurePackID = "23b570e2-61f8-40ca-8e4d-7625ac7a4d37"
$webApplicationURL = "https://myserver"
$url = "https://test.mysharepoint.com" 
$owneralias = "TEST\SP_App01"
$contentDatabase = "WSS_Content_WebApp01"
$template = "STS#0"

$sub = New-SPSiteSubscription

if(!$url.StartsWith("https://")){ $url = "https://$url"; }
if(!$url.StartsWith($webApplicationURL))
{ 
    $hostheader = 'y' 
} 

#Set Feature Pack
if ($featurePackID -ne "")
{
    $FeaturePack = Get-SPSiteSubscriptionFeaturePack $featurePackID
}
if($FeaturePack -ne "" -and $FeaturePack -ne $null){
  Set-SPSiteSubscriptionConfig $sub -FeaturePack $FeaturePack
}

if($hostheader -ieq 'y' -or $hostheader -ieq 'yes'){
  #Pre-Reqs
  if( (Get-SPManagedPath -HostHeader "admin" -ea SilentlyContinue) -eq $null){$void = New-SPManagedPath "admin" -hostheader -explicit}

  $wa = Get-SPWebApplication $webApplicationURL
  New-SPSite $url -owneralias $owneralias -sitesubscription $sub -hostheaderwebapplication $wa -template $template -contentdatabase $contentdatabase #| set-spsite -maxsize 5000000 -warningsize 4000000 
  New-SPSite "$url/admin" -owneralias $owneralias -sitesubscription $sub -template "TENANTADMIN#0" -Administrationsitetype "TenantAdministration" -hostheaderwebapplication $wa -contentdatabase $contentdatabase #| set-spsite -maxsize 5000000 -warningsize 4000000 

}
else{
  New-SPSite $url -owneralias $owneralias -sitesubscription $sub -template "STS#0" | set-spsite -maxsize 5000000 -warningsize 4000000
  New-SPSite "$url/admin" -owneralias $owneralias -sitesubscription $sub -template "TENANTADMIN#0" -Administrationsitetype "TenantAdministration" | set-spsite -maxsize 5000000 -warningsize 400000
}

However I'm getting the following error:

New-SPSite : Object reference not set to an instance of an object. + New-SPSite <<<< $url -owneralias $owneralias -sitesubscription $sub -hostheaderwebapplication $wa -template $template -contentdata base $contentdatabase #| set-spsite -maxsize 5000000 -warningsize 4000000 + CategoryInfo : InvalidData: (Microsoft.Share...SPCmdletNewSite:SPCmdletNewSite) [New-SPSite], NullReferenceException + FullyQualifiedErrorId : Microsoft.SharePoint.PowerShell.SPCmdletNewSite

Any ideas why?

Answer 1

This turned out to be a permissions error. I re-ran the script, without specifying the template, but set my account as the OwnerAlias. Then I ran this script to set the template:

Get-SPSite https://test.mysharepoint.com | Set-SPSite -Template "TenantAdmin#0" -Administrationsitetype "TenantAdministration"

And hey presto - all working. Then I went in and changed the Owner happily.