Do not under estimate the power of a reboot for your modem and, or Wi-Fi Router.
Success rates of upward of 80% of fixing your internet connectivity issue! A simple power cycle can fix an arrangement of issues that are unforeseen. We're using electronics, and it sometimes happens!
To power cycle your modem, simply unplug and plug the modem and wait at least 30 seconds, and power back up. That's it.