Since the last software update which was maybe 2 weeks ago, I can't get notifications from an app called Mattermost, which I use for my work.
In the notification settings menu, notifications for this app are off and can't be turned on (can toggle on but just goes straight back to off again). It's also classed as a system app which doesn't seem right. I've made sure that the battery setting for the app is unrestricted, I've cleared it's data, uninstalled, rebooted, reinstalled from Google play (so it's definitely up to date) and it's the same. This happens over WiFi and mobile data connections, and the phone is not in do not disturb mode. All permissions for the app are enabled. The app works fine in all other ways, it's just that the phone is blocking notifications from it, with no way to stop this.
I ever tried to re-install Android System webview, but with no luck. Please, help me.