Recent versions of Jerboa aren't compatible with Lemmy v0.17.x, which lemmy.world still runs until some performance issues get ironed out.
You can install Jerboa v0.34 from F-droid, Obtainium, or by downloading the APK from Jerboa's github. Uninstall first if you installed from the play store.
Cool, FYI lemmy.world has been upgraded to v0.18.x.now and is compatible with recent Jerboa's for the last few days. I've run Jerboa v0.37 from F-droid recently, as well as v0.38 via obtanium. No issues anymore. I'd recommend to upgrade again if you haven't already.
They've tried a couple times to update and it's causing problems (that version of Lemmy). The expectation I last heard for the release of the next version is a week or so.
In the meantime, you can try a different android app (like Liftoff) or run the Progressive Webapp from Chrome by opening Lemmy.world and choosing "install app" from the ellipsis at the top right. It'll install your instance as an app.