https://moosh.im/mooshimeter/specs/

Resistance
Better than 1% accuracy over 20 Ohms – 20 Megaohms

So, there are no promises of resistance measurements under 20 ohms. You can still measure those, but need to at least zero your leads (and meter itself) to get about realistic values.

There’s (a little bit) more about it:
https://moosh.im/wiki/index.php/Small_Resistance_Measurements