Hey again, Here are some steps that have worked for me in the past with similar network issues, Hope one or all helps out. (And forgive me if these steps were previously posted):
Although many use VPN’s on Mac’s you may not have to completely uninstall it but in System Preferences > Network If there is a VPN interface on the left column, click on it and hit the “-“ to remove it. (Can be added later).
Create a new network location:
In the same spot next to “Locations” on the top click on it, click “Edit Locations”, hit the “+” to add one, give it a unique name, hit “Done” then “Apply” on the bottom.
This will disconnect the network for a few seconds usually.
In those SAME settings, hit “Advanced” on the bottom right > Proxies, if anything in here is enabled other than the very bottom one, that you or your network administrator didn’t configure, de-select it, hit “Done” and again “Apply”,
Next go to System Preferences > Users and Groups > Login Items, remove (even temporarily) all of the items below in the same fashion.”.
Hir the Apple Logo > Restart, be sure to un-check the option to re open apps, then hit “Restart”.
Test the issue after that.
Also making sure the date, time, time zone and region to make sure they are correct (Even though it was working fine before the update), this can all be done in System Preferences.
If those options fail, do a Time Machine backup, save a separate copy of these files if need be and then delete:
Finder > Go > Computer > Macintosh HD (Usually) > Library:
Save and delete all the contents of:
Extensions (Except Apple Mobile Device)
Internet Plugins
Launch Agents
Launch Daemons
Scripting Additions
Startup Items
(I might do the same for the ~/Library (Hidden).
Restart and test.
I’d say if it still happens and across all good networks and users yet other devices connect fine:
First boot your Mac to recovery mode:
Startup holding Command R,
When there, click on “Get Help Online” (Connect to your network first).
If it works just fine here, but not while logged into any admin account, or safe boot, or across any good network, and the above steps failed:
Backup up this folder also in the /Library:
Preferences/System Configuration/,
Then delete from inside the folder:
Preferences.plist
(You might also see a Preferences.plist(Old) as well, remove that as well if there.
Network Interfaces.plist
Com.apple.airport.preferences.plist
Restart and test again.
It’s not as tedious as it seems most of those steps just take a minute or so, so hope some of the first steps help, they’re worth a try, considering it’s kind of important to connect to the internet nowadays!
Worst comes to worst, and it works while in recovery mode, backup/erase/install if needed, hope it works out!
I’d try the net location first if you haven’t, and definitely any VPN interface.
https://support.apple.com/en-us/HT202480
