Some users said that the system settings system backup page showed that the button for manual backup was gray, and many Android phone brands were similar, unable to back up the data to the cloud.
Unfortunately, Google has yet to respond to the issue. It is worth noting that some users post in XDA forum to provide a temporary solution to fix the problem through ADB command. Note that you need to install the device driver, turn on USB debugging, and connect to the PC before executing the ADB command.