Turn off "auto fit content"
In the latest week, our Email Designers tackled a challenge with mobile optimization in the native email client for Samsung Phones. The challenge became apparent when we started noticing that the desktop version was being presented of the template, instead of the mobile version.
After testing and research, our designers concluded the underlying reason is a setting of “Auto fit content”. Presented in the settings menu of the Samsung email client. By turning this setting off your emails may become mobile optimized again!