i phone 5 s running ios 10.2.1 can't install .ipa files.

Hi. So my cousin gave me her old i phone 5 that's running ios 10. JB'd it with double h3lixand installed appsync on it. Also installed appcake. However when I try to install an ipa file appcake just says failed to install and gives an error code -999. Anything I can do to fix this?
Thanks a lot

I would guess that it's something about signing issues. I'm not sure about compatibility, but you could try reprovision from the following repo:
https://repo.incendo.ws
Kind regards
Tobias

okeee, I got some apps installed like papa sangre 2 and Audio defense, but other things like bop it! still don't work. Ill try that.

While im talking about jb's what things should I install on this?

Please remember to tag your post. I believe yours is a [Question]. As for what tweaks to install, perhaps you could grab Springtomize to speed up your phone, bootsound to get a nice bootsound when booting up your phone, batchomatic to back up your tweaks, and more. I would just look at featured tweaks and see what fits your wants.
Kind regards
Tobias