I added a custom font both on Shopify code and on PageFly. It is working fine both on pc and Android, but it is hardly readable on iPhone (on the left in image).
This is Victor from PageFly - Shopify Page Builder App, I’d like to suggest this idea:
About this, if you check on the default page the font error still appears, then you should check the font you uploaded, if my suggestions don’t work well, please contact our 24/7 live chat support to discuss more and fix it.