Desktop notifications not working

Im having an Issue where me and my friends dont get Notifications for new messages. The test notifications are working fine.

I’ve set the notification prefferences in the account settings and the channel settings so that I should get a notification for every messages, yet I dont get any at all.
Another thing I’ve noticed is that my window starts flashing as if I would select and deselect it.

Using Windows 10 for the Client

Using Ubuntu 16.04 for the Server
Installed the server a day ago through the manual installation because My server provicder doesnt allow me to use snaps :frowning:

Hope you guys can help me with this.

Are you running SSL on your server? We had trouble with notifications being delivered consistently until we went SSL.