The QuickBooks API's Bill, Company info, Tax Agency etc are not working with all fields invalid query error is observed Are any fields deprecated ?

Let me route you to the right support that can help you with your QuickBooks API concerns, sandstonesaascre.

There's a community dedicated to developers and integrating other websites with QuickBooks. They'll help you with resolving the invalid query error of QuickBooks API fields. Just post your question to our separate online forum called Intuit Developer Community. 

From there, our Intuit Developer can provide you with further details to get back the QuickBooks API's Bill, Company info, Tax Agency, and other fields working again. Let me guide you on how: 

1. Go to this link: https://help.developer.intuit.com/s/.
2. Choose QuickBooks Online under What do you need help with? 
3. Click Ask a Question. 
4. Log into your existing Intuit Developer Account or create a new one. 
5. Enter your concern. 
6. Click Ask. 

Additionally, you can always utilize the API Docs & Tools and Blog menu on the Intuit Developer's page. From there, you can check out the latest feature added to the application.

Please post again or leave a comment on this thread should you have any additional questions or concerns about QuickBooks API. I'm always here to answer them. Take good care!