I have a SaaS based website that creates a subdomain for each client (so it creates a website and a pool for each subdomain) and it is hosted on IIS.

I used these two scripts scripts to remove some unused websites & pools (there was +100 subdomain or so).

at first everything seemed fine but after few hrs a lot of websites started not responding although they had nothing to do with the removed sites and they didn't work again unless the pool & website are removed then added again (recycles didn't work).

Why did these scripts cause a problem??

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Import-Module WebAdministration

Get-Website |
Where-Object {
$_.Name -match '(?i)^.+\.siteName.*$' -and

    \# Exclusions (case-insensitive via (?i))  
    $\_.Name -notmatch '(?i)^firstSubdomain' -and  
    $\_.Name -notmatch '(?i)^secondSubdomain' -and  

    $\_.Name -notmatch '(?i)^siteName$'  
} |  
ForEach-Object {  
    Write-Host "Removing site: $($\_.Name)"  
    Remove-Website -Name $\_.Name  
}  

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Import-Module WebAdministration
Get-ChildItem IIS:\AppPools |
Where-Object {
$_.Name -match '(?i)^.+\.siteName.*$' -and

    \# Exclusions (case-insensitive)  
    $\_.Name -notmatch '(?i)^firstSubdomain' -and  
    $\_.Name -notmatch '(?i)^secondSubdomain' -and  

    $\_.Name -notmatch '(?i)^siteName$'  
} |  
ForEach-Object {  
    Write-Host "Removing App Pool: $($\_.Name)"  
    Remove-WebAppPool -Name $\_.Name  

}