First of all, please make sure you are using the latest version of your bank app. This is easy to do, simply visit the Apple AppStore (for iPhone users) or Google Play (for Android users), look for your bank app, and check the app does not need updating.
If you are on the latest version and your bank app does not open when redirected by the Marygold app or notifications, then please contact us. It is likely to be a small technical issue with either your bank, Moneyhub or us. Either way, we'd like to investigate it and get it fixed asap.