How to Fix QuickBooks Desktop Error H303 (Issue with Multi-User Hosting)?

QuickBooks Error H303 occurs when the software cannot connect to a company file on another computer due to a multi-user hosting issue. This issue occurs due to incorrect hosting settings, firewall blocks, or network problems. Common causes include wrong hosting settings on the server, firewall restrictions, missing or damaged network data files (.ND), and incorrect DNS settings. 

To fix this error, users should check hosting settings, adjust firewall rules, run QuickBooks Database Server Manager, and verify network configurations. Maintaining the correct system setup and a stable network can prevent this error.  Here are 5 methods to fix this QuickBooks Desktop Error H303.

Method 1: Run the QuickBooks File Doctor Tool

QuickBooks File Doctor fixes company file and component issues. Download and run it to resolve the error.

Steps to Use QuickBooks File Doctor:

1. Close QuickBooks.
2. Download QuickBooks Tools Hub on the server computer.
3. Install it by running the downloaded file and following on-screen instructions.
4. Open QuickBooks Tool Hub > Go to Company File Issues.

5. Click Run QuickBooks File Doctor.
6. Select your company file from the drop-down menu.
7. Choose the correct repair option and click Continue.
8. Enter your QuickBooks password and click Next.

Fix Network Issues Using QuickBooks Database Server Manager:

1. Open QuickBooks Tool Hub > Go to Network Issues.
2. Click QuickBooks Database Server Manager.
3. Select Start Scan to detect and fix firewall issues.
4. Once the scan finishes, click Close.

The tool scans for damaged files and repairs them. After the process, open QuickBooks and check if the error is resolved. 

Method 2: Verifying the Hosting Setting in QuickBooks

Incorrect hosting settings can cause Error H303. Follow these steps to check and fix them:

1. Open QuickBooks on all servers and workstations.
2. Go to File > Utilities.
3. Click Stop Hosting Multi-User Configuration (if enabled).
4. Restart QuickBooks.

5. Go to File > Utilities > Host Multi-User Configuration.
6. Restart your system and check if the issue is resolved.

After this, review and change Firewall Settings if needed.

Method 3: Configure with Firewall Authentication

The firewall may block QuickBooks from connecting to other systems, causing Error H303. Follow these steps to allow access:

1. Open the Control Panel from the Start menu.
2. Go to Firewall Settings.
3. Click Allow a program through the firewall.
4. Select Add Programs and add QuickBooks to the exception list.
5. Restart your computer for changes to apply.

Method 4: Change the Setting of File Locations

QuickBooks may fail to locate the company file due to access issues. Moving the file can help resolve the problem. Follow these steps:

1. Create a new folder on the server.
2. Enable sharing by setting Windows access permissions.
3. Copy the Company File (.QBW) and paste it into the new folder.
4. Update the file location on the workstation.
5. Open the Company File from the workstation.

Method 5: Check QuickBooks services on your server

Ensure QuickBooksDBXX and QBCFMonitorService are running on the server:

1. Press Windows + R, type services.msc, and press Enter.
2. Find QuickBooksDBXX and double-click it.
3. Select Automatic as the Startup type.
4. Click Start if the status isn’t running.
5. Go to the Recovery tab and set First, Second, and Subsequent Failure to Restart the Service.
6. Click Apply > OK.
7. Repeat for QBCFMonitorService.
8. Open QuickBooks on workstations and switch to multi-user mode.

Method 6: Add services to the group of Windows Admin User

Multi-user settings need proper permissions to avoid Error H303. Follow these steps to grant access:

Allow Full Control to QBDataServiceUserXX:

1. Right-click the company file folder and select Properties.
2. Go to the Security tab and click Edit.
3. Select QBDataServiceUserXX, check Allow Full Control, then click Apply.
4. Click OK to save changes.

Enable Windows File Sharing:

1. Press Windows + E to open File Explorer.
2. Right-click the company file folder and select Properties.
3. Click the Sharing tab, then click Add.
4. Select QBDataServiceUserXX and grant Full Control.
5. Click Share to apply changes.

Restart QuickBooks and check if multi-user mode works properly.

Method 7: Allow QuickBooks Through Windows Firewall

Windows Firewall may block QuickBooks, preventing access to the company file. Follow these steps to configure the firewall and allow QuickBooks:

1. Open Windows Firewall from the Start menu.
2. Go to Advanced Settings > Inbound Rules > New Rule.
3. Select Port > Next > TCP.
4. Enter the specific ports based on your QuickBooks version:
   • QB 2020: 8019, XXXXX
   • QB 2019: 8019, XXXXX
   • QB 2018: 8019, 56728, 55378-55382
   • QB 2017: 8019, 56727, 55373-55377

(XXXXX is the dynamic port for QB 2019 and later versions.)

5. Click Next after entering the port number.
6. Select Allow the connection, then click Next. 
7. Select all profiles, then click Next.
8. Name the rule (e.g., QBPorts2020) and click Finish.

Method 8: Run an anti-malware scan

Malware or viruses can interfere with QuickBooks and cause errors. Follow these steps to scan and protect your system:

• Run an anti-malware scan to detect and remove threats.
• Ensure QuickBooks is not flagged as a threat by security software.
• Use reliable security applications for system protection.

What are the Prerequisites to Fix QuickBooks Desktop  Error H303?

1. Connect all computers to the same network.
2. Install the latest version.
3. Use an admin account.
4. Only the server should host the file.
5. Allow QuickBooks through security settings
6.  Install and run on the server.
7. Store the file in a shared with proper permissions.

How to Identify QuickBooks Desktop  Error H303?

1. Pop-up with error message “This company file is on another computer, and QuickBooks needs some help connecting”
2. QuickBooks won’t switch modes.
3. Workstations can’t open the file.
4. QuickBooks lags or freezes.
5. Connection issues between systems.

How to Prevent QuickBooks Error H303?

1. Only the server should host the file.
2. Keep all systems on a stable connection.
3. Allow QuickBooks through security settings.
4. Keep QuickBooks and Windows updated.
5. Run it regularly for stability.
6. Set correct sharing and permissions.
7. Monitor for lags or errors.

When Should You Seek Professional Help for QuickBooks Desktop  Error H303?

You should seek professional help for QuickBooks Error H303 if the error persists after applying basic troubleshooting steps like configuring hosting settings, adjusting firewall permissions, and running QuickBooks Database Server Manager. If QuickBooks still fails to connect in multi-user mode, the company file remains inaccessible, or network issues continue, expert assistance is necessary. Also, if you notice frequent crashes, data loss risks, or complex network configuration issues beyond your expertise, contacting a QuickBooks professional ensures a proper resolution without further complications.