Oh wow, font problems on the 'Kindle' app are one of those small, annoying things that can ruin a cozy reading session — but most of them are fixable with a few checks and tricks. I usually start with the obvious: close the app, force-stop it if you can, then reopen. If that doesn’t help, I toggle airplane mode on and off and re-sync; sometimes the app needs to re-download the book metadata. Next I dive into the in-app settings: tap the font icon and try switching fonts, sizes, line spacing, and margins. There's often a toggle called 'Publisher Font' (or similar) — switching that off will force the app to use its default fonts and reflow the text, which fixes weird line breaks or odd glyphs for many books.

If the problem is missing characters, like strange boxes instead of letters or poor rendering for languages with non-Latin scripts, the culprit can be a fonts issue in the book file itself. For reflowable ebooks you can try deleting the book from the device and re-downloading it from the cloud; if that fails, re-downloading the whole app cache (clear cache on Android or reinstall) sometimes helps. For fixed-layout books and PDFs there’s less wiggle room — they’re basically images or locked layouts. In those cases I either use a dedicated PDF reader or convert the file to a reflowable format. I’ve had good results using Calibre to convert PDFs or to embed better fonts into MOBI/AZW3 files, but do back up the original file first.

If you’re on Android and fancy tinkering, 'Kindle' sometimes supports custom fonts: you can drop .ttf/.otf files into the app’s fonts folder on your device storage (paths vary by device and OS version, so a quick web search for the current folder is smart), then restart the app and pick the new font from the menu. iOS is more locked down — custom fonts are limited unless you use a system-wide font app or jailbreak, which I won’t recommend. On desktop apps the font options are simpler; if the desktop reader still misrenders, try sending the book to your device via USB or using the web reader at read.amazon.com to see if it’s a device-specific rendering bug.

Finally, if nothing fixes it, contact Amazon support or the publisher. I once reported a badly formatted reprint and the publisher uploaded a corrected file within a week — surprisingly quick. Little tip: keep notes of which titles misbehave and screenshots to speed up support. Between toggling 'Publisher Font', re-downloading, trying a conversion tool like Calibre, and reaching out to support, most font gremlins can be chased off, and then it’s back to uninterrupted reading.