[BUG] [P1] None of our customers is able to log in

[vladaman]

Description:
Our application has been using Android SDK version 3.1.1 for several years, successfully deployed across hundreds of devices. Recently, all of our clients have become unable to log in.

Troubleshooting performed:
We attempted to resolve the issue by upgrading to SDK version 7.0.0, but the login problem persists.

Expected behavior:
Users should be able to authenticate successfully.

Actual behavior:
All login attempts fail for every client.

Additional context:

• The issue started suddenly after years of stable operation
• No changes were made to our authentication implementation prior to the failure
• The problem affects all deployed devices

Upgrading to the latest SDK 7.0.0 did not resolve the issue

2026-05-01 17:56:51.143 30800-30800 SumUp   V  (SourceFile:1)@main | clearAccessToken() called
2026-05-01 17:56:51.144 30800-30800 SumUp   V  (LoginActivity.java:1)@main | logInWithPassword()
2026-05-01 17:56:51.159 30800-30800 SumUp   V  (rpcReaderManager.java:5)@main | postAction() called with: action = [com.sumup.merchant.reader.identitylib.network.rpcActions.rpcActionLoginWithPassword@f5553b3], progress = [com.sumup.merchant.reader.identitylib.ui.activities.LoginActivity$AffiliateLoginHandler@6475d70], needToken = [false]
2026-05-01 17:56:51.197 30800-30993 SumUp   D  (SourceFile:1)@Thread-15 | Intercepting login call
2026-05-01 17:56:51.674 30800-30993 SumUp   D  (SourceFile:5)@Thread-15 | TLS version: TLS_1_2, CipherSuite: TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
2026-05-01 17:56:51.680 30800-30800 SumUp   E  (rpcReaderManager.java:33)@main | Event rpcEventLogin - Reason: Zadané přihlašovací údaje jsou neplatné. Prosím, zkontrolujte vaše jméno a heslo a zkuste to znovu.
2026-05-01 17:56:51.700 30800-30800 SumUp   V  (LoginActivity.java:1)@main | onError() called with: event = [com.sumup.merchant.reader.identitylib.network.rpcEvents.rpcEventLogin@65ead39]
2026-05-01 17:56:51.701 30800-30800 SumUp   V  (LoginActivity.java:1)@main | isAutoLoginInProgress() called
2026-05-01 17:56:51.702 30800-30800 SumUp   D  (SourceFile:1)@main | postEvent() called with: event = com.sumup.merchant.reader.identitylib.event.LoginErrorEvent@22d4f7e
2026-05-01 17:56:51.712 30800-30965 SumUp   D  (SourceFile:1)@pool-18-thread-2 | LoginErrorEvent event posted, details: com.sumup.merchant.reader.identitylib.event.LoginErrorEvent@22d4f7e
2026-05-01 17:56:51.715 30800-30800 SumUp   D  (LoginActivity.java:16)@main | Login failed.
2026-05-01 17:56:52.073 30800-30800 SumUp   V  (LoginActivity.java:1)@main | updateUiForState() called with: newState = [IDLE], the previous state was: = [LOGIN_IN_PROGRESS]
2026-05-01 17:56:52.074 30800-30800 SumUp   D  (LoginActivity.java:1)@main | Updating UI for state: IDLE
2026-05-01 17:56:52.091 30800-30800 SumUp   V  (LoginActivity.java:40)@main | Showing idle UI

[matoous]

Hi @vladaman, could you please share a bit more details regarding your integration? OAuth2 client ID, Affiliate Key, or Merchant code of the merchant under which you have the developer settings would help us lookup logs and traces on our side.

I tried to lookup the information based on your email address but your merchant account doesn't have any developer settings.

[HeyPouya]

@vladaman I’m closing this issue for now since we haven’t heard back. Please feel free to reopen it if you’re still experiencing the issue or if it reoccurs.