The content is licensed for personal use only, not commercial use. The
content may not be used in any way whatsoever in which you charge money,
collect fees, or receive any form of remuneration. The content may not be
resold, relicensed, sub-licensed, rented, leased, or used in advertising.

If you want to use this font for commercial purposes, you can buy the license here:
https://fontbundles.net/ahargun-shop/728885-serotonon-calligraphy-font