Check for user in a group in a different domain - powershell

Question

I am stuck with a piece of code.
We have 2 AD domains with users and groups in them.
I am trying to run a script that will check if the user is a member of a group to disable EV access and if they are not a member of that group add them to the EV enable group.
I have this working for 1 domain but I can't get it to work across the 2 domains we have.
I want the script to check domain1 and add it to the group in domain1 but if it doesn't find the user check domain2 and add it to the group in domain2.
Below is an extract of the code I have but I am struggling to get it to recognise the domain controller so that it looks in the right domain for the user.
foreach ($u in $Users){
Foreach($domain in $Domainlist)
{
$dom =get-addomain $domain.name
$dm = $dom.distinguishedname
$dname = $dom.name
$DomName = $dom.DNSRoot
$ADdc = Get-addomaincontroller -discover -domain $domName
$dc = $ADdc.hostname
$User = Get-ADUser $u.name -server $dc
$Enablegroup = "cn=evenable,ou=users and computers," + $dom
$disablegroup = "cn=evdisable,ou=users and computers," + $dom
if ((Get-ADUser $u.name -server $dc -Properties memberof).memberof -eq $disablegroup)
{
$name = $u.name
$dm = $domain.name
Write-host "$name is a member of the $dm EV disable group" -f Yellow
}

Answer 1

This is not hard at all!
Basically we just replace one line with the following, and we use PowerShell's try/catch syntax. Try this first chunk of code, if you have an error, then do the second part instead.
From
$User = Get-ADUser $u.name -server $dc
To
try{ $User = Get-ADUser $u.name -server $dc -ErrorAction STOP}
catch {$User = Get-ADUser $u.name -server OtherDC -ErrorAction STOP
$dom =get-addomain OtherDomain}
The whole goal of a structure like this is to handle the branching logic of try this/if it fails, do this instead, and ensure that the script will keep running after that point. So, because you're using $dom in the later part of the script to resolve the full path of the Security Group, you also need to change the $dom value in the Catch block, as I've done above.
Just tweak these values as appropriate for your domain and it should just work. I used an approach very similar to this for a task of my own, and Try/Catch/Finally was exactly the tool to get the job done.