Look for a check box in the router WAN settings entitled 'Use These DNS Servers'. Make sure that box is checked.
I found this tip on the following page: https://www.element14.com/community/thread/42793/l/rpi-network-working-but-no-internet?displayfullthread=true
Unfortunately still no luck, tried manually changing to other DNS servers as well. This is really getting frustrating. It's the year 2018 and we're talking about using a WORKING wifi connection on a device that is proven to be CAPABLE of using the same connection.
Anyways, thanks for all your suggestions guys. Please keep them coming so we get a solution. 
Did you try a wired ethernet connection ?
Also try rebooting your router.
Try channel 6 & 11
Try another router
Still not able to locate the problem.
b) User has added extra wireless routers in their network and they are configured as routers so they create a second subnet (instead of using them as a bridge to extend the current subnet) so the wirelessly connected HTPC box is behind a NAT gateway and not contactable.
I made this fatal mistake recently and chewit's quote is what i had done.
Same symptoms as yours i was connected but no internet on the one box.
Just throwing it in here JUST in case.
Same Problem for me, no idea why... connected but without netowrk connection.
As with any networking issues, there are 2 places to look at first: the networking equipment (router) and the device having the issue (computer, smartphone, tablet etc.). As a first step, restart your networking equipment and device and see if that fixes the problem. As with the router, network, wifi, and software problems often get fixed automatically with a simple restart. If it doesn't help you, check with the following:
Check Modem Lights
Flush your DNS
Change your DNS server address
IP address conflict
Outdated network driver
Check your ISP's status
Same ptobl for me .
DHCP lease ok but no internet on the latest 9.2.3 release.
Any news about this? I'm having the same issue. I tried Kodi with another OS and work perfectly. I think the problem is Librelec. I tried 9.2.4, 9.2.0 and 9.0.1 and the isso continues.
I'm seeing the same issue with two different (Intel) machines. Internal network communication is working 100%. Pinging out to 8.8.8.8, 1.1.1.1 and every internet IP works from SSH, but Kodi/LibreELEC can't communicate. Very strange issue.
I had the same issue , then I disabled both wifi and wired internet connection, enabled the wired connection, restarted the Raspberry pi 4 and it was fixed. But I dont know if this will work for ya
same Problem here after a router change. So it's router I guess.
Still looking.
