When you go to System Settings -> Battery, what do you see? Can you see the percentage there? If so, you should let the battery charge to around 100%, then let it discharge to around 10% or so, then reconnect the charger and let it charge up again to 100% to see if the message goes away after putting the battery through a full charge cycle. You could also try booting into [link|https://support.apple.com/guide/mac-help/start-up-your-mac-in-safe-mode-mh21245/mac|Safe Mode|new_window=true] to see if this fixes the issue. In the worst case scenario, there may be a defect with the battery you installed. Good luck!