You get HTTP 500 after Exchange Security Update (SU)

 (Get-AuthConfig).CurrentCertificateThumbprint | Get-ExchangeCertificate | Format-List

New-ExchangeCertificate -KeySize 2048 -PrivateKeyExportable $true -SubjectName "cn=Microsoft Exchange Server Auth Certificate" -FriendlyName "Microsoft Exchange Server Auth Certificate" -DomainName @()

Set-AuthConfig -NewCertificateThumbprint <ThumbprintFromStep1> -NewCertificateEffectiveDate (Get-Date)

Set-AuthConfig -PublishCertificate

Set-AuthConfig -ClearPreviousCertificate

IISReset