Notes app can't connect to nextcloud account

When I try to connect my android Notes app, nothing happens and I receive an error message. I believe it is a server error and not due to the android app.

Steps to reproduce

1. open Notes app
2. press on 'Choose account'
3. select account (connected through Nextcloud app) and press 'ok'

Expected behaviour

Connect to nextcloud server Notes

Actual behaviour

Nothing happens and an error message is reported

Server

Please complete the following information.

• Notes app version: 4.12.1
• Nextcloud version: 31.0.6
• OS: DSM 7.2.2-72806 Update 3
• Web server: appache http server 2.4
• PHP version: 8.2
• Database: MariaDB 10

Nextcloud configuration:

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "192.168.0.*",
            "maylo.familyds.org",
            "nextcloud.maylo.org"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "31.0.6.2",
        "overwrite.cli.url": "https:\/\/192.168.0.15\/nextcloud",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "filelocking.enabled": false,
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "maintenance": false,
        "theme": "",
        "loglevel": 0,
        "default_phone_region": "CH",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpsecure": "ssl",
        "maintenance_window_start": 100,
        "secret": "***REMOVED SENSITIVE VALUE***",
        "app_install_overwrite": []
    }
}

Client

Please complete the following information.

• Browser (incl. version):
• OS: e-OS 3.0.1, android 13

Log files

App Version: 4.3.1
App Version Code: 40030190
App Flavor: fdroid

Files App Version Code: 30310490 (PROD)

---

OS Version: 4.9.337-perf+(eng.root.20250606.143826)
OS API Level: 33
Device: FP3
Manufacturer: Fairphone
Model (and Product): FP3 (lineage_FP3)

---

com.nextcloud.android.sso.exceptions.NextcloudHttpRequestFailedException: HTTP request failed with HTTP status-code: 500
	at com.nextcloud.android.sso.api.AidlNetworkRequest.performNetworkRequestV2(AidlNetworkRequest.java:179)
	at com.nextcloud.android.sso.api.NextcloudAPI.performNetworkRequestV2(NextcloudAPI.java:159)
	at com.nextcloud.android.sso.api.NextcloudAPI.lambda$performRequestObservableV2$0(NextcloudAPI.java:97)
	at com.nextcloud.android.sso.api.NextcloudAPI.$r8$lambda$af7W9mq2B0ZrhVJwZd-ibFp8T3Y(Unknown Source:0)
	at com.nextcloud.android.sso.api.NextcloudAPI$$ExternalSyntheticLambda1.subscribe(D8$$SyntheticClass:0)
	at io.reactivex.internal.operators.observable.ObservableFromPublisher.subscribeActual(ObservableFromPublisher.java:31)
	at io.reactivex.Observable.subscribe(Observable.java:12284)
	at io.reactivex.internal.operators.observable.ObservableSingleMaybe.subscribeActual(ObservableSingleMaybe.java:31)
	at io.reactivex.Maybe.subscribe(Maybe.java:4290)
	at io.reactivex.Maybe.blockingGet(Maybe.java:2320)
	at io.reactivex.Observable.blockingSingle(Observable.java:5381)
	at it.niedermann.owncloud.notes.persistence.CapabilitiesClient.getCapabilities(CapabilitiesClient.java:38)
	at it.niedermann.owncloud.notes.importaccount.ImportAccountActivity.lambda$onActivityResult$5(ImportAccountActivity.java:102)
	at it.niedermann.owncloud.notes.importaccount.ImportAccountActivity.$r8$lambda$wIJzzcgrzM9d6k7exwdLMn3GvgQ(Unknown Source:0)
	at it.niedermann.owncloud.notes.importaccount.ImportAccountActivity$$ExternalSyntheticLambda4.run(D8$$SyntheticClass:0)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:463)
	at java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1137)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:637)
	at java.lang.Thread.run(Thread.java:1012)
Caused by: java.lang.IllegalStateException: {"ocs":{"meta":{"status":"failure","statuscode":996,"message":"Internal Server Error\n"},"data":[]}}

	at com.nextcloud.android.sso.InputStreamBinder.processRequestV2(InputStreamBinder.java:440)
	at com.nextcloud.android.sso.InputStreamBinder.performNextcloudRequestAndBodyStreamV2(InputStreamBinder.java:113)
	at com.nextcloud.android.sso.InputStreamBinder.performNextcloudRequestV2(InputStreamBinder.java:96)
	at com.nextcloud.android.sso.aidl.IInputStreamService$Stub.onTransact(IInputStreamService.java:108)
	at android.os.Binder.execTransactInternal(Binder.java:1280)
	at android.os.Binder.execTransact(Binder.java:1244)

Start with the Android stack trace at ImportAccountActivity.java:102 and CapabilitiesClient.java:38, then inspect the Nextcloud server response and logs for the HTTP 500. Reproduce the account import with the listed app and server versions; done means the account connects without the reported error.