Let's try some browser troubleshooting steps to fix this, dana7.

When creating an expense, you'd need to select a bank account type from the Bank/Credit account drop-down. Since you've tried using all the options and got the same error, kindly check if it also happens when using a private window.

When you're able to save the transaction there, go back to your previous browser and clear the cache. You can also do this task on a different browser like Google Chrome, Internet Explorer, or Mozilla Firefox.

Let me know how it goes after trying out these steps. I'll be right here to help you further.