The Sparda-Bank Hessen switched to a different IT system provider on March 9Th 2025: https://www.sparda-hessen.de/hilfe-und-service/fragen-und-antworten/it-wechsel-2025.html

We already updated Outbank accordingly. To update your login data,  please follow the steps below:
‘Settings’ > ‘Bank credentials’ > ‘Select Sparda-Bank München login’ > ‘Add your new credentials’ > ‘Done’ > ‘Update configuration’