According to your description, if your mobile phone cannot be upgraded through FOTA, I suggest you:

1. To verify whether the network environment is stable, it is recommended to use WLAN wireless network.

2. The mobile phone is fully charged (above 50%)

3. Sufficient storage space for the mobile phone (at least 1GB USB memory).

4. Please wait patiently or try to upgrade at another time. It may be related to network stability and servers.

5. If you still can't upgrade through FOTA, it is recommended that you install kies software in your computer, connect it with a data cable and click Update at the bottom of the pop-up window. Connect the computer through kies and update the firmware. The following is the upgrade method of Samsung official website KIES software for your reference:

/support/skp/faq/447063

6. You can also bring the purchase invoice, maintenance card and machine to Samsung Service Center, and the engineer will check and upgrade the machine. Please click the following link to find out the specific location of Samsung Service Center:

. Samsung . com/support/service locations . ASP

If you have any comments, suggestions and comments, please click: support.samsung.com.cn/survey.