The government's cyber-security office says almost three-quarters of scam emails reported to it last month imitated Manx Telecom.
The Office of Cyber-Security and Information Assurance says in July people reported 990 suspicious emails.
And it says of those, 70 per cent were phishing attempts pretending to be manx.net mails.
It says if you think an email you receive is suspicious, you can report it here.