Your drivers might be up to date according to Microsoft driver update utility, but actually many a times after an upgrade to windows 10 your previous drivers get replaced by Microsoft drivers which require you to download appropriate drivers from your manufacturers website. You should check under device manager what driver are you using, if it is the one from your manufacturer its okay but if it is from Microsoft i strongly recommend to download the correct driver for your wlan card from the website of your manufacturer.
Further if you already have the drivers form your manufacturer , have you tried uninstalling and reinstalling the driver? You can do that through device manager, uninstall current driver for your wlan and reboot your device , then your system will reinstall the drivers back again.