Unable to sign in to Apple ID in SideStore ("The data couldn't be read because it isn't in the correct format.")

[idk137891]

Hi,

I'm having an issue signing in to my Apple ID in the SideStore app.

Environment

• Device: iPhone 17
• iOS: 26.4.2
• SideStore: 3.7.2 (0603)
• iLoader: 2.2.6

Problem

Whenever I try to sign in with my Apple ID inside SideStore, I successfully receive and enter the 2FA verification code, but then SideStore immediately shows this error:

"The data couldn't be read because it isn't in the correct format."

The login never completes.

What I've already tried

• Reset adi.pb
• Reinstalled SideStore
• Tested both Stable and Nightly builds
• Used multiple different Anisette servers
• Created and tested a custom Anisette server list (including additional community servers)
• Tested LocalDevVPN (App Store version)
• Tried both Wi-Fi and cellular data
• Tried with and without a regular VPN
• Used a completely different Apple ID
• Signed the new Apple ID into iPhone Settings first
• Successfully received and entered the 2FA verification code
• Confirmed that the same Apple ID can sign in successfully using iLoader

What I've confirmed

• The Anisette server is reachable.
• iLoader works normally.
• The problem only occurs inside the SideStore app.
• The exact same error occurs every time after entering the verification code.
• The issue also happens with different Apple IDs.

Additional information

• I live in mainland China.
• I have already posted this in the official Discord support forum and pinged the Helper role, but I haven't received a response after more than one day.
• Another community member also reported experiencing a very similar issue on a different device.
• A community member also pointed me to a Reddit thread discussing similar problems affecting users in mainland China and France, but the suggested workaround did not resolve my issue.

Is there anything else I can test?

Or could this be a SideStore bug?

English is not my native language, so I used AI to help me write this post. If anything is unclear, I'll be happy to explain further.

Thank you very much for your time.

[yaf480977898-creator]

I am in the same situation as well.

[TonyMontanah]

Me too same problem

[EVA0M3]

我遇到类似的问题目前登陆appleid报错503，也尝试过你上面说的方法都不行,请问一下你找到解决方法了吗，我用AI工具查说是苹果服务器的问题