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That might mean you have malware (or software corruption) on your Acer laptop.
Tell me: does the laptop have any anti-virus utility, or Firewall, on it?
Thank you - you may ignore the solicitation for additional services (and with them, charges). I did not send that message to you, the website system did. (And I have no control over such messages.)
Well... what email software are you using?
Try sending the same email in webmail - using a web browser, logging in to your email account on a web browser - and see if it is reported as sending multiple times. If it does not, then the problem is in your software (that you normally use) for emailing.
If it does still, then the problem is in your email provider's own servers, not on your laptop.
If it only happened once.... then maybe it was just fortuitous, an accident, not likely to be repeated!
After all: you have a good anti-virus uility, Kaspersky, on your computer.
If your computer is less than a year old, it is of course covered by warranty.