If the problem happens on PowerPoint, maybe it is because you don’t have the font installed on your computer.
We usually use Google Fonts. They are free, and you can download them here.
The name of the font we use is mentioned on the last slide of the presentation. Just look it up on Google Fonts website, download it and install it on your computer.
This should not happen with a Google Slide template, since Google Slides supports Google Fonts.
If you still have issues with fonts not looking right, you can send us an e-mail to hello@slidesmania.com and we will do our best to assist you.