Hello Nonee!

You'll need to configure both the server and the workstations. This is to ensure that both computers will be able to run QuickBooks Desktop without issues.

Also, it's best to seek some assistance from your IT personnel so they can further assist you with it. You check this article and follow the steps on Step 3: Configure firewall manually section: Set up firewall and security settings for QuickBooks Desktop.

Post again here if you need more help. Take care!

Hopefully this helps whoever is still having issues with Windows firewall blocking QuickBooks.

Even with firewall off and antivirus off I would still get the message that windows firewall was blocking QuickBooks.

On the pc holding the company file to be accessed-I reset all firewall settings to default.

Then I typed in allow application through firewall in the search box.

Scrolled through the allowed applications.

QuickBooks was an allowed application but QuickBooks version 21 was not.

Clicked on "change settings"-then clicked on "allow another app"-then hit the "browse" button and searched the QuickBooks 21 version.

I added that version to "Allowed apps to communicate through windows firewall", rebooted my system and I can now access QuickBooks. 

Yes! Thank you, userdww. Creating inbound and outbound firewall rules for the appropriate QB ports worked for me. Like others in this thread, I spent hours on QB suggestions (about 20 pages of them) to solve the multi-user problem and they were no help at all. Five minutes of firewall rule creation solved the problem. It's troubling that the QB program and tools purport to do this already.  

Following the below-given steps to fix windows firewall is blocking QuickBooks issue.

Click on the Windows icon and select, Control Panel.
Go to the Windows Firewall window and locate where it says: “Windows firewall with adv. s.”
Then, choose New Rule and click on Program.
After that, mark the This program Path checkbox.
Browse and choose the components for the service that you want to allow. You can do this by simultaneously pressing the Ctrl + F option.
Go to the next window and choose the Allow the connection option. Then, click Next.
Further, make sure to mark every checkbox that appears on your screen.
At last, you have to enter the name of the rule. For example: Payroll Allow.
Follow the same steps for allowing the outbound connection. For this, select the outbound option and then click on create a rule. After that, open the QuickBooks Desktop application. If the Windows firewall is blocking QuickBooks issue persists even then, try to turn off the Windows firewall.

hey, I just had the same issue you have in this conversation, I wish to know if you have got help, so that you also advise me accordingly.