If you successfully authorised the transfer in your bank app but the transfer is showing as 'declined' in Marygold it means that your bank provider has subsequently declined the request to allow the transfer even though you authorised it.
This is unusual but not impossible, and is not something that Marygold can typically help you with. The most common reason why this might occur is something as simple as not having sufficient funds in your Primary Account. Other reasons can include things like your bank being concerned that the authorised transfer is highly unusual and them wanting to protect you.
This is a decision your bank has made about the transfer request you have authorised. If the proposed transfer was large, you could try again but using a smaller amount, or you could ask your bank why they are blocking the transfer. If you have persistent problems with your bank provider we would like to know, to see if we can work with your bank to re-assure them that this is a simple payment from one bank account in your name to another bank account in your name.