Managing personal Outlook.com account settings, security, and privacy
Hello DONKUHN1
Any pop-up telling you to call a phone number to resolve any kind of problem is a SCAM no matter who it states it's from and especially if it states that it's for Microsoft Support.
That type of message is not uncommon and is triggered by the web site that was last visited. I don't have a ChromeBook but have a relative who had a real knack for running into those messages on his Windows PC.