Hi @Андрей Михалевский,
Please create a rule with the following cmdlet and see if it works for you:
New-TransportRule -Name "block TLD .com" -FromAddressMatchesPatterns "\w+@\w+\.com$" -RejectMessageReasonText "blocked" -StopRuleProcessing $true
This regax (\w+@\w+.com$) will check if the sender email address ends with .com.
If yes, the rule will block the email.
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