Some browsers and operating systems support pressure sensitivity out of the box, while others require more work. First of all, open https://magma.com/, click on the hamburger icon, and select Help, then "Getting started".
You will see a list of browsers, along with instructions for each of them.
We recommend using Google Chrome - it's a robust, modern browser with excellent performance, guaranteeing a smooth drawing experience.
If the above does not help, please make sure you try all of the following as well:
Make sure you're using Google Chrome and it's updated to the latest version;
Check your table device settings and if you find any of the following options, make sure they're enabled: Windows Ink / Tablet PC / Digital Ink
Install and enable our Google Chrome extension
If you’re using a computer with a macOS system, try disconnecting or reconnecting your mouse (in some cases moving the mouse while drawing at the same time might cause issues)
Reboot your computer and try again