
Xiaomi has rolled out Android 16 update to a few phones, with a wider availability expected with the HyperOS 3. The latest iteration of HyperOS is still in beta preview, the same as the new Android OS. Unfortunately, it seems to be causing some issues connecting to Google Photos.
Xiaomi phones run Android and come pre-installed with some Google apps. One of them is Google Photos, and it’s a great addition as it allows uploading and storing photos in the cloud. Unfortunately, that has not been working properly since the Android 16 upgrade. While only a few people are experiencing the problem, Xiaomi seems to be on top of it.
Details of Xiaomi Android 16 phones are unable to connect to Google Photos

Since the upgrade to Android 16, there have been reports of failed uploads and downloads. The bug made it difficult to connect to Google Photos, making the experience with the app unpleasant, especially when downloading photos from the cloud.
Fortunately, the problem is with the App and not with Xiaomi. It means the issue will be fixed quickly, and that seems to be the case. A new update was released on September 1st via the Play Store. It addresses the bug for Xiaomi users and everyone having the same problem.
We recommend checking for a new update on the Play Store if you are still having problems with the Google Photos app. Also, ensure to clear the app cache after installing the latest update.
source: Xiaomi