This 2011 MBA is updated to High Sierra. I have tried to connect to 5 different WiFi networks but in all cases, the MBA can connect to local network but no Internet.
All 5 of these networks are professionally configured in hotels.
Running Diagnostics seems to say everything is ok. Also, at the same time I can connect to the same networks with another Macbook Air (2013, Mojave) and two different iPhones (8 and 6s) with no problems.
If I turn on Personal Hotspot in either of the two iPhones, the 2011 MBA obtains Internet no problem and gives a fast connection.
The 2011 MBA used to work fine on wifi with no problems. It may be that updating the OS has somehow caused a problem, but I'm not the primary user of the 2011 machine and am not sure if the problem appeared with HS or was there before.
Does anyone have any suggestions to troubleshoot a WiFi connection that doesn't get to the internet?