Full Error Message:
sObject type ‘rsdoc__Document_Action__c’ is not supported. If you are attempting to use a custom object, be sure to append the ‘__c’ after the entity name. Please reference your WSDL or the describe call for the appropriate names.

Reply: 
You may see this error message is your app subscription was suspended due to 4 failed payment attempts to your credit card on file in AppExchange. The billing contact would have received an email each time app payment failed to let you know it would be suspended on 4th automated attempt. You will need to reactivate the app subscription by following these instructions. Make sure you are logged into only your Production Salesforce org and related AppExchange account when reactivating or modifying your app subscription.