Unable to backup MySQL

Hi, I’m new to this world, I’m trying to backup various databases in MySQL but I keep getting this error

mysqldump failed :

/usr/bin/mysqldump: unknown variable 'connect_timeout=28800'

How can i solve?

MariaDB version 10.1.45
Usermin version 1.803
Webmin version 1.955

Due to various problems I cannot update my versions.
Thank you a lot

check your mysql/mariadb config files. somewhere under [mysqldump] section you have this variable that shouldn’t be there. remove it and retry.

I found the mysqldump file in the /usr/bin/ directory.
Should I open the file or remove it directly?

nope you must not remove the binary file in /usr/bin

but edit a config file for mysql which should be in /etc/mysql or $HOME/.my.cnf

Perfect it worked. Removing the string connect_timeout ha works. Thanks a lot