App sometimes not installing on watch series 4

Hi,


I released my first watch app for an existing iOS app some days ago and I get user feedback, that it refuses to install on some series 4 watches. It works on our watch 4 and on many others, but on some it just won't install properly. It either hangs while installing or won't install at all - even after resetting both devices.


The watch app is 3MB in size.

Does anyone has an idea, what may cause this behavior? Anything I can improve to avoid this setup-wise?


I called Apple support and they already have some reports like this for different apps, but no real solution other than reset iPhone and watch.


Thanks!