Why are fonts in my plots different when downloaded from a shinyapps.io-deployed app?

I have an app which makes a ggplot. There is also a downloadHandler section in the code to download the plot as an SVG image.

When the code is deployed on my local (Windows) machine, the font is Font#1 (Let's call it this for simplicity, I think it may be either Calibri or Arial, not sure). When I download the SVG image, the plot looks exactly the same as in the app - still Font#1

When I deploy this app to my shinyapps.io account, and go to the deployed link, the plot still looks the same - Font#1. However, when the plot is downloaded, the font changes to a different Font#2.


I searched around online, and tried options(CairoFonts(regular="FreeSans:style=Medium")) from the Cairo library , but nothing seems to be making a difference.

Also, I tried explicitly controlling the fonts within theme, like so: text=element_text(size=13,family="Calibri")). This effects all but the downloaded-from-app plots, aka the ones with a problem in the first place.

How can I fix this so that the fonts are always like the original, Font#1 ?

*The screenshot should be sufficient, but if it would help to make a reprex of the code and deploy it to an app, then screenshot that - I would be glad to.*