Do you mean that after an update that your network is not being recognised or that an update has failed due to a network failure during update?
If the update was completed( you can check that in settings) then just select your network anew, or if the update failed re run it. Again in settings, updates and security, then check in update history or check for updates after ensuring that the network is recognised. If it will not recognise the network you may have to "go back to previous version" in settings , update and security, "recovery".