Steps by steps instructions to fix QuickBooks Error H303
Give below are some quick solutions that can be followed in order to troubleshoot the QuickBooks error H303. In case, you find it difficult to get rid of the same and unable to apply the solutions, get in touch with our QuickBooks experts:

Solution 1: Check your Firewall Settings

First of all, you have to choose the Control Panel and choose Firewall Settings.
After that, click on Allow a program via firewall.
You are required to click on Add programs & QuickBooks 20xx in the exception list.
Finally, re-launch the QuickBooks software.
Solution 2: Try to use the QuickBooks File Doctor Tool

First of all, you have to install the QuickBooks file doctor tool in your PC.
After that, access the QuickBooks file doctor tool.
Finally, try to fix the QuickBooks Error Code H303 associated with QuickBooks multi-user hosting.
Solution 3: Correct your PC settings

Firstly, you are required to launch QuickBooks in multi-user mode.
After that, you have to click on files on both computers.
Choose Files and select Utilities.
And then, choose Stop Hosting Multi-user configuration.
Finally, launch the file on both PCs.
Solution 4: Change the QuickBooks Folders location

Firstly, you need to create a new folder in the hosting PC.
After that, set and share Windows access permissions to permit you to share the files.
You have to copy .qbw file and then, paste it in a new folder.
Finally, try to run the company file.