Hardware: First thing to check is the Router:
Is your router unplugged or did power to it cut out? Your solution may be as simple as restarting your router or plugging it back in.
Did your Wi-Fi password change recently? You may need to re-enter the new password in your device if it didn’t automatically save the changed passkey.
Are other websites or internet browsers working? Sometimes, certain websites or servers go down. Check other sites or use another web browser to verify whether it’s your Wi-Fi or just a specific site. (Chrome, Firefox, Edge etc).
Are you able to connect when moving a bit closer to the router? If you can connect after moving closer, you may have a range problem rather than a Wi-Fi connection issue. This can be solved by getting a Wi-Fi range extender.
Troubleshoot device connectivity issues
Next would be to troubleshoot your machine:
The first and most important step to start with is to restart your device. This is the standard basic troubleshooting and 9 times out of 10 is the fix to the problem.
Your next step is to check your network adapter. This being making sure the wifi has been turned on for this device. If you normally work via cable at work some devices have Wi-Fi (wireless) disabled by default.
* Your network adapter can be found on the bottom right-hand corner of the taskbar.
* On a Mac, look for the Wi-Fi (AirPort) card in the top right corner of your screen (next to the sound and battery icons in your menu). Click on the option to “Turn Wi-Fi On.”
Another step to troubleshooting is to see if your machine is missing any updates. A lot of the time when updating your machine, it will install all drivers your machine might be missing or are out of date and therefore not working as they should.
* To update your machine – Start button/ Settings/ update and Security/ check for updates (let this run its list, if any, and restart your machine)
Another issue could be hardware, although not as common, sometimes the network adapter may stop working for numerous reasons including overheating and reaching the lifespan of the component. This will require a replacement.
Internet service provider issues
Another thing to keep in mind is, it might not even be your side that’s having the problem. If you have restarted your router and all came back up normally your ISP might be having some issues.
You can check this information by going to the support page on their website and checking if they have an outage which could be affecting your connection. If this is, the case, there is nothing to be done but wait it out.