In JIRA Cloud, when we try to import JIRA Server Backup using "Restore system" option, its throwing an error as attached below.

I tried with multiple fresh backup from JIRA Server but it's not working. Below is the file hierarchy of backup file
File name: Jira-v7-cloud-migration-backup.zip
->activeobjects.xml (in root folder)
->entities.xml (in root folder)
PS: The same import method with same backup file was working well till day before yesterday (ET). But since yesterday, am facing these issue.