After every reboot apps can't use the network On a Xiaomi Mi 5. Android version 7.1.2 MIUI Global 8.5.

After every rebook I get the message "Can't use the Network" every time an app starts. 

This is how it looks for Telegram:
argh. the UX of this thing sucks.
basically i always clicked on the "allow" because that's the only button in the figure. but if one clicks on the notification dialog, outside of the "allow" button then the corresponding settings page is opened where one can enable the use of Network for all the apps. this is what i ended up doing.  (another bad usability pattern: settings page is unfindable in any other way)