It happens to everyone eventually. For whatever reason, the card you used to pay for your session didn't go through on the site and needs reprocessing. This is a very easy fix.
If you are a GM looking for how to add your bank account for payouts, please check out this FAQ article!
How to Update Your Payment Method:
Go to your Account Settings
Click on Payment
Under Payment method, enter in your:
New card number
Expiration date
CVC/CVV
Click Save
