Unknown Error when Selecting a plan (20004)

If you see the message "Unknown error, please contact customer support (20004)" when trying to purchase a Sidus Link Pro subscription, it means the app was unable to retrieve your App Store account credentials. This is typically an account verification or sign-in issue — not a payment problem.

Try the following steps in order:

Step 1: Verify Your Apple ID Email

If you recently created a new Apple ID, your email may not be verified yet.

1. Open Settings on your device.
2. Tap your name at the top, then go to Sign-In & Security.
3. If prompted, verify your email address.
4. Return to Sidus Link Pro and try subscribing again.

Step 2: Re-Sign Into the App Store

If your email is already verified, try refreshing your App Store session.

1. Open the App Store.
2. Tap your profile icon and sign out of your account.
3. Go back to Sidus Link Pro and attempt to subscribe.
4. When prompted, sign in with your App Store account.

Step 3: Reinstall Sidus Link Pro

If the issue persists after trying Steps 1 and 2:

1. Delete Sidus Link Pro from your device.
2. Reinstall it from the App Store.
3. Open the app and try purchasing your subscription again.

Still Need Help?

If none of the above steps resolve the issue, please contact our support team at support@aputure.com with the following details:

- Your Apple ID email address

- Your device model and iOS version

- A screenshot of the error message