I have the ABN AMRO app working on the latest (3.7.3-a15-20260506618655-official-FP6) version, but a different phone. I have relocked the bootloader. Haven’t done anything special.
Thuis information is nog really useful since it doesn’t give you any solutions, but maybe it gives you some hope to make it work again.
You can raise an issue in Gitlab with these details. That would help the developers to debug this. They may also want you to generate logs in required.
Ok, it has been resolved. When I upgraded to 3.7.3 I upgraded ABNAMRO as well, and it failed. After upgrading to 4.0, I just used the same app which kept failing.
This morning I deleted the ABNAMRO app, and reinstalled from scratch. Now it appears to be working. So I think the bug was in 3.7.3, and resolved in 4.0.