Hello there, @ThangTran.

I appreciate you for sharing the steps you performed to resolve the issue. Since it persists, I recommend contacting our Customer Care Team. This way, they'll be able to check further the main cause of the error "Cannot communicate with the company file ".

Here's how:

1. From the Help menu, select QuickBooks Desktop Help.
2. Click Contact Us.
3. Share a brief description of your concern in the dialogue box.
4. Click Search.
5. You can either select Get a Callback or Start a message.

Due to the ongoing pandemic, we have limited staff at the moment. This is the reason some of our support channels are only available during business hours. To ensure that you'll be assisted on time, please check out our support hours.

Also, you can always visit our Help articles page for reference. There, you can read some of the helpful articles that will guide you in your future tasks.

Please keep me posted on how it goes, ThangTran. Take care always.

@ThangTran 

Try copy the QBW file to your local machine and open it. If the same error persists, your company file is damaged. Call and ask Intuit Data Service to fix it. Otherwise, consider purchasing a 3rd party file repair service.

Funny thing is, I tried to copy the file to other folder on the same server. It temporary works for 1-2 days then it happened again. 

I tried to contact supporter through chat. We don't have solution yet. Can you guy on higher support level jump in and help. It's very urgent for our company!

I tried to contact supporters through chat. We don't have a solution yet. Can you guy on higher support level jump in and help. It's very urgent for our company

Run the Verify/Rebuild Data tool. Did you find any error message? Next step, secure a backup file and restore it with a different name. Use and monitor that file for the same error pattern.

We recently upgrade from QB Premier Professional Services 2019 to 2021. Our setup is a server and one workstation. The problem is that the workstation cannot open the company file when someone is accessing the file on the server. If no one is logged on the server, the workstation connects to the file just fine. The error I get is:

@Andy__22 

How many user license do you have? A license for 2 users or 2 licenses for single user?

Have you enabled the multiuser mode on your file?

My issue was the modem from AT&T

 I swapped it and now no issues