lost connection while doing transaction

[Warner Krelekamp]

I have a database with a table energie that is 2.5GB.
The application (NodeRed) cannot update the tabel, gets an error.
I tried:
MariaDB [Huismanager]> check table energie;
ERROR 2013 (HY000): Lost connection to MySQL server during query

When making a backup with HeidiSQL I get different errors. I once got the error that the index was corrupt. So I tried:
MariaDB [Huismanager]> optimize table energie;
ERROR 2013 (HY000): Lost connection to MySQL server during query

The server is running on a virtual machine with debian11 and Node-Red.