Hello and welcome to Apple Support Communities gabrielamartin1,
We see that you're having an issue opening your banking app on your Apple Watch. We know that it is a great convenience to be able to access these apps on your Apple Watch, and we'd be happy to help.
First, let's make sure that your Apple Watch is set to mirror your iPhone. Go to the Watch app on your iPhone > Bank of America app > Mirror my iPhone.
If these settings are already set, restart your Apple Watch, then test to see if the issue remains.
How to restart your Apple Watch
If the issue persists, remove the app from the Apple Watch and then reinstall. The article below will guide you through removing the app.
Organize apps on Apple Watch
Let us know how this goes.
Have a great day!