Why has the sms delivery notification sound + confirmation suddenly stopped?

[AC Question]

Xiaomi MI4i MIUI 8.2.2.0.

When using the phone's default Messaging app, I had the following selections (which I have not changed).
Settings - Messaging - Notifications - Delivery Status On, Delivery Sound On. I used to see "Received" on the left of the message sent and also a hear a sound. These notifications have suddenly stopped. I have made no changes in Settings ( I double checked), and I have not switched networks. Would someone be able to help with this? Thank you.

 

[B. Diddy]

Welcome to Android Central! Do you still see the Received at the left of the message, but just don't hear the tone?

 

[RohiniChoudh]

Welcome to Android Central! Do you still see the Received at the left of the message, but just don't hear the tone?

Hi, no the Received note does not appear any more either.

 

[B. Diddy]

And all other notifications continue to work normally?

Any power-saving modes turned on? Try wiping the cache partition: XIAOMI Mi 4 - Recovery Mode - HardReset.info.

 

[B. Diddy]

And all other notifications continue to work normally?

Any power-saving modes turned on? Try wiping the cache partition: XIAOMI Mi 4 - Recovery Mode - HardReset.info.