MariaDB backup error

I start backup my DB, get error:
mariadbdump.sql: mysqldump: Error 2013: Lost connection to MySQL server during query when dumping tablexxxat row: 453

DB size is not large: 15-20Mb.
In SSH command:
mysqldump -u{user} -p{pass} --all-databases > backup.sql, works great.
What am I doing wrong?