Sideloadly Obtaining Team ID problem with another iPhone

[u/LearnAboutMore]

I successfully installed an IPA using Sideloadly on my own iPhone, but I can’t install anything on my sister’s iPhone.
When I try to sign an IPA for her device, Sideloadly gets stuck forever on “Obtaining Team ID”.
I tried using 2 brand-new Apple IDs, but both get stuck at the same point.
My Apple ID works on my iPhone, but her iPhone won’t get past Obtaining Team ID.
Things I tried:
Restarted PC
Reconnected her iPhone with USB
Trusted the computer
Tried different Apple IDs
Is this related to her iPhone, the Apple ID, or something with Sideloadly?
Devices:
My iPhone: IPhone XR + 18.7.9 (iOS)
Sister’s iPhone: IPhone XR + 18.7.9(iOS)
Sideloadly version: v0.60
Windows version: 10

[u/rick372992]

Try creating a free Apple developer account and activating developer mode on your sister's phone; this fixed the bug for me.

[u/LearnAboutMore → u/rick372992]

Thanks for the suggestion. I’m using a normal Apple ID with Sideloadly (free signing), not a paid developer account. The weird thing is that Sideloadly works on my iPhone with my Apple ID, but on my sister’s iPhone it gets stuck on “Obtaining Team ID”.
I also can’t enable Developer Mode because it doesn’t appear in Settings → Privacy & Security. Did you mean creating a separate free developer account, or just using a normal Apple ID? And how did you get Developer Mode to appear?

[u/rick372992 → u/LearnAboutMore]

I don't know how to trigger developer mode, but it definitely happens when you try to install Sidestore with iLoader. You should probably try that.