Often Outlook (and Edge browser as well) will think I'm still on a metered connection after I've connected to WiFi. This usually keeps the apps offline even if I say it's ok to continue. Also provide proper sync on metered connection with Outlook 2016
Only rebooting the PC will help solve the problem.
Philippe A. Schnyder commented
When using Outlook on a metered connection it keeps asking if one wants to use Outlook over a meted connection.
This is very annoying and should be disabeable by configuration.
This has been an issue for many users: http://answers.microsoft.com/en-us/office/forum/office_2013_release-outlook/office-2013-how-disable-message-of-metered/5dffe813-ff19-437a-a1ea-5eb80c9ba8f3?auth=1
(and no: I don't want to make the connection unmetered, because it is e.g. appreciated that Windows Updates are not downloaded)