connection_timeout parameter is defined as

"To enable them, define the timeout in seconds in the service's configuration section."

https://mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-configuration-usage-scenarios/#connection_timeout

But the setter use function config_truth_value() to check the parameter, but
config_truth_value returns an error("Not a boolean value"), if the value is unequal 0 or 1.

serviceSetTimeout(service, config_truth_value(connection_timeout));

config_truth_value(char *str)
{
if (strcasecmp(str, "true") == 0 || strcasecmp(str, "on") == 0 ||
strcasecmp(str, "yes") == 0 || strcasecmp(str, "1") == 0)

if (strcasecmp(str, "false") == 0 || strcasecmp(str, "off") == 0 ||
strcasecmp(str, "no") == 0 || strcasecmp(str, "0") == 0)

MXS_ERROR("Not a boolean value: %s", str);
return -1;
To reproduce:
add
connection_timeout=3600
to a services configuration.

Suggested fix:

remove function config_truth_value

serviceSetTimeout(service, connection_timeout);