Enable the debug mode as below to trace the error for netdata plugins
#/usr/libexec/netdata/plugins.d/python.d.plugin 1 debug module_name
#/usr/libexec/netdata/plugins.d/python.d.plugin dns_query_time debug trace 1
#/usr/libexec/netdata/plugins.d/node.d.plugin 1 debug snmp