Hi. I'm David, and I'm happy to help you.
This phone number is a scam. Microsoft does not include phone numbers in error messages or warnings, and any pop‑up urging you to call is a fraudulent attempt to steal personal or financial information. Do not call this number. Close the pop‑up and run a trusted security scan instead as a precaution.
To better understand how these scams work and how to protect yourself, see this official Microsoft article:
Feel free to ask any questions you may have.