hey I'm sorry I know this is about wattpad, but I'm using this as a moment to make a public service announcement. this not solely directed at prev (although it is also partially directed at prev) and I want to be clear that there is 100% no reason that you're expected to know this, I am not blaming anybody for being fooled
AO3 doesn't have an official app
AO3 is optimized to run in your mobile browser, because they don't really have the people, time, money to spare developing and maintaining an app.
if you're using an app on your phone or tablet to access AO3 it's 100% an unofficial third-party app, and not by the Organization for Transformative Works.
if it says 'official' app, its still not one. it's an unofficial app. they are lying. they're using the logo and everything, too, but they are not an official AO3 app. I found two like this, and I had to look to find the 'we are an unofficial app'.
for the sketchiness of that alone, I would recommend deleting the app and changing your AO3 password. I'm not your dad, I can't tell you what to do, this is just advice that's intended to be helpful and friendly.
I know a lot of the internet doesn't work well in the mobile browser but I swear AO3 works great! You can even make your own skins to change how the page looks for you! (Or use skins that other people have made, there's lots out there!) Or you can download the fics and use them in an ereader of your choice, if you prefer.
just be really careful, because this AO3 app situation comes up every now and again. sometimes it's well-meaning fans, sometimes it's not.
if AO3 ever does put an app out- which is not on the roadmap as far as I'm aware- you'll be able to find lots of information about it on the AO3 website, confirming that it's genuine will be easy-peasy.