Hey all!
I’ve fixed this issue before simply by creating a new network location, just takes a second:
How to use network locations on your Mac:
https://support.apple.com/en-us/HT202480
In short:
Open System Preferences > Network.
On the top next to “Locations”, select the drop down menu, usually set to “Automatic”.
Select Edit Locations.
Click the “+” to add a location.
Give it a name, (Usually such as your location, Home, Office, etc. or just leave as Untitled).
Click Okay or Done.
Then in the bottom right, click “Apply”.
The network will disconnect for just a few seconds then re-connect.
Restart the Mac and try again.
This is a safe and quick troubleshooting step. If all is working fine, great, if you need to, you can just delete the previous network location by clicking the “-“ instead.
Otherwise, I do find that having security software installed can be an issue.
In particular in the same Network Preferences:
On the left column, if you have any type of “VPN” highlight it and click the “-“ below to remove it, then, again click “Apply” on the bottom right, restart and test.
This may not be the case for everyone, but worth a look, cheers.