Is this a Firefox error message?

Hello, It is most likely a fake notification. First, if you cant close it externally (try not to click the notification x icon unless its the actual windows push notification (still fake), then close Firefox and restart. Once you restart, you can try disabling permissions to remove this popup. First, go to menu > settings > privacy & security, scroll down to permissions, and click the settings for it next to notifications. Then, look through the list of websites, and if you see a sketchy domain or a domain that is posing as a "official" domain, remove it. Next, check if the currently installed extensions are verified or if you have any that are unrecognized, remove them. Lastly, run a malware scan by your antimalware service to check for any viruses.