Manx Telecom says people will have to pay for their manx.net email addresses from next year.
The company says it's transferring its email system to specialist email provider Junara, which will provide the service in future.
Users are being told to go to manx.net and register for the new service, which will cost £65 a year or £6.50 a month.
If email addresses at manx.net, isleofman.com and isleofman.org aren't registered by January 20 next year, they'll be suspended the following day.
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