ERROR 2013 (HY000) Lost connection to MySQL server during query - with Maria DB

Question

I saw How to Prevent Connection Timeouts for Large MySQL Imports but it didn't help. I have checked the parameters of server.cnf in /etc/my.cnf.d/

 max_allowed_packet = 32M
 key_buffer_size = 3G
 innodb_buffer_size = 15G
 thread_cache_size = 50
 thread_stack = 192K

The DB is 250 Gb. The disk space is ok. I try a full import with the following command as root after drop database schema and create empty one :

sh -c 'nohup mysql -uroot -p*** --default-character-set=utf8 myschema < mysqlschemafullbackup.sql &'

MariaDB version : 10.3.39 on centOS 7.9 Can you help me solving this?

Kind regards,

I tried to launch the command 3 times and it stopped at various Gb size of the DB 19 Gb then 39 Gb.