We've investigated this and found out that you need to make sure that Wells Fargo has your correct and current telephone numbers on account. When authenticating, it will prompt you which number to use (if you have multiple). Once you choose one, you should receive a code to that phone within one minute and that's the code you need to enter in MoneyWiz.
Hope this helps.
Can you please try once again signing into your Wells Fargo account website to check if you're asked for the same?