Application is not working on my Xiaomi

1) For MIUI 8

a. Allow running in background - Open the Settings - Tap the Battery & performance - Tap the Manage apps battery usage - Tap the Choose apps - Find and tap the Should I Answer - Set Background Settings to No restrictions

b. Disable Power Saving (If allow running in background not work) - Open the Settings - Tap the Battery & performance - Tap the Manage apps battery usage - Tap the Power Saving Modes > Off

c. Enable Start in background - Open the Settings - Tap the Installed apps - Find and tap the Should I Answer - Tap the Other permissions - Enable the Start in background

d. Enable notifications on lock screen - Open the Settings - Tap the Installed apps - Find and tap the Should I Answer - Tap the Custom notification - Enable the Lock screen notifications - Press Back - Tap the Other permissions - Enable the Show on Lock screen