I'm having this weird issue that both of my custom plugin logs are not working but all other third party ones including craft.log work fine. By 'not working' I mean the log file is generated, but empty.
Another weird thing is the issue only happens on production environment. Tested on local environment and staging environment, they all work fine.
I believe I got the code right?
MyPlugin::log("Errors:\n\n" . print_r($fieldsData, true), LogLevel::Error);
It's Craft 2 by the way.