Notice about unable to charge monthly subscription key.This is the 2nd time while trying to run payroll. What can I do to fix this?

You came to the right place. I'd love to offer assistance in updating the billing information and setting up an account for payment. 

To change the payment method for the QuickBooks Online account, here's how:

1. Click the Gear Icon.
2. Go to Account and Settings.
3. Select Billing & Subscription.
4. Enter the credit card information. (Card number, name on card, expiration date, and security code.) 
5. Make sure to verify the billing address in QuickBooks Online is the same address on the credit card statement.
6. Click Save Changes.

For additional reference, please check this article: Update payment method for QuickBooks Online subscription.

If your bank isn't supported by QuickBooks' please our phone support for further assistance. Feel free to reach them through this link: Get help with QuickBooks Online.

Don't hesitate to leave your comment by clicking the Reply button below if you have other concerns about updating your payment method. Have a good one.