Windows – Missing Gmail notifications in windows 10 action center

Well after some research and contacting Microsoft Support I found out the following:

Like Indrek said, only Metro/Live tile apps can show notifications on the lock screen, however the Mail app can NOT be simply synched with Outlook to display notifications on the lock screen. In order to do that you have to add your e-mail address manually and separately in the Mail app.

My problem stemmed from the fact that my e-mail address is a corporate e-mail and it does not use neither POP3 nor IMAP, it uses Microsoft Exchange. That is why it was unable to sync my emails. Please note it is an hp.com e-mail and not an Exchange e-mail address, as it appears there is a difference between Microsoft Exchange e-mail protocol and the Microsoft Exchange e-mail... program/service/whatever.

Short answer for tech savvy people: You need to manually set your mail server address and username in order to sync a Microsoft Exchange protocol e-mail.

To set up your Microsoft Exchange protocol email you need to add an account in the Mail app by opening the Mail app and pressing "Win + C" then going to "Settings" and "Accounts". Click "Add an account" and choose "Other" as the type of account. Choose "IMAP" and click "Show more details" on the next screen, here you need to fill out all the details, namely username and incoming/outgoing server - you may need to ask a system administrator to do this for you. After you do that your Mail app should sync.

In the Settings app, go to System > Notifications & actions, find Outlook and turn off the toggle in the same row.

Personally, I found it better to let the toggle on, click the whole Outlook row and disable just the "Show notifications in action center" toggle on the page that appears. The notifications are still on, but they vanish from the Action center once the notification banner hides.