Backup failed

Greetings rokonuzzaman32,

Welcome to Apple Support Communities. From the attached photo, its looks as if the backup is taking longer than expected. These steps can help with that:

"If your iCloud backup is taking longer than expected to complete

1. Check that you're connected to Wi-Fi.
2. Check your upload speed.
3. Leave your device connected to power and Wi-Fi for 24 hours. If your backup still isn't done, archive important data then contact Apple Support. "

Further troubleshooting can be found in the Apple Support article:

If you can't back up to iCloud - Apple Support

Feel free to reach back out if you have any questions.

Best regards!