QBM Connection Troubleshooting Guide

What this guide covers: connection problems only (when QBM Client cannot connect to QBM Server / database).
Typical setup: QBM Client → QBM Server (Windows Service) → Microsoft SQL Server.

Quick rule:

If more than one QBM client cannot connect at the same time, the issue is usually on the server side (QBM Server and/or SQL Server), not on individual computers.
If only one user cannot connect, the issue is likely on that PC or its local network.

1) Server-side checks (most common)

✅ 1. Check QBM Server Windows Service

QBM Server runs as a Windows Service on your server.

Log in to the QBM Server machine.
Open Services (press Win+R → type services.msc → Enter).
Locate QBM Server (name may appear as “QBMServer” or similar).
If the service is Stopped: Right-click → Start.
If it is Running but clients cannot connect: Right-click → Restart.

Important: Set the service startup type to:
Automatic (Delayed Start)

✅ 2. Check SQL Server Service (Very Important)

QBM Server depends on Microsoft SQL Server. If SQL Server is stopped, QBM Server cannot work and all clients will lose connection.

In Services, locate one of the following:
- SQL Server (MSSQLSERVER) (default instance)
- SQL Server (YourInstanceName) (named instance)
Make sure the status is Running.
If it is Stopped: Right-click → Start.
If it is running but unstable: Right-click → Restart.

If your QBM settings specify a particular SQL instance name, that exact instance must be installed and running.

✅ 3. Restart the Windows Server (if needed)

If restarting services does not resolve the issue:

Restart the Windows Server.
After reboot, confirm that SQL Server and QBM Server start automatically.

This often resolves temporary service-level issues.

✅ 4. Additional server checks

Please also verify:

The server has network connectivity (LAN / VPN as applicable).
Windows Updates are not waiting for a restart.
Firewall or antivirus has not blocked QBM Server or SQL Server.
The server has enough free disk space.
System date and time are correct.

2) Client-side checks (when only one PC is affected)

✅ Verify the connection settings in QBM

In QBM, confirm the server address, port, and SQL instance settings are correct.

Settings location: File → Data Utilities → Settings

Check:

Server address (server name or IP)
Port (if your configuration uses a specific port)
SQL Server instance name (must match the SQL service installed on the server)
Database name (must exist on SQL Server and be accessible)
User ID / password (case sensitive)
Connection type (LAN / VPN if your environment uses VPN)

Important: If the client settings point to the wrong SQL instance name, QBM may show messages indicating the instance is not installed or not started.

✅ Basic network checks

From the affected PC:

Confirm you can reach the server (e.g., open File Explorer and try \\ServerName if applicable, or ping if allowed in your network).
If you use VPN: confirm VPN is connected and stable, then try again.
Temporarily disable “over-restrictive” security software policies (only if your IT policy allows) or ask IT to whitelist QBM.
Restart the affected PC (this often clears stuck network sessions).

3) Common connection error messages (and what to do)

The messages below are commonly produced by QBM when a connection to the server, service endpoint, or SQL Server fails.

What you may see	Meaning (typical)	What to do
“No connection could be established” or “No connection could be made… target machine…”	The server is unreachable, the service is down, firewall is blocking, or the address/port is wrong.	On the server: restart QBM Server service. Confirm the server is online and reachable from the client network/VPN. Check firewall rules on the server for QBM traffic and SQL traffic. Verify QBM settings (server address/port).
“Endpoint not found” or “remote endpoint is no longer available”	QBM client cannot reach the service endpoint (QBM Server service not reachable or not running).	Restart QBM Server Windows Service. Verify server address/port in QBM settings. Check firewall/antivirus on the server.
“net.tcp:// …” or “Invalid URI”	The server address/URI is incorrect, incomplete, or not reachable.	Re-check the server address in `File → Data Utilities → Settings`. Correct typos (server name, IP, port). Confirm DNS (if using server name instead of IP).
Timeout (e.g., “System.TimeoutException”)	The request to server/SQL is taking too long or the connection is unstable.	Restart QBM Server service and SQL Server service. Check server load (CPU/RAM/Disk). Check network stability (VPN drops or LAN issues).
“CommunicationException” or “ServiceChannel … Faulted state” or “channel can no longer be used…”	The service communication channel became faulted (server-side interruption, network drop, or restart).	Close QBM and reopen it. If multiple users are affected: restart QBM Server service. Confirm firewall/antivirus did not block the service.
SQL Error 11 (SQL Server not started / not accessible)	SQL Server service is not started or SQL is not responding correctly.	Start/Restart the SQL Server service on the server. Confirm the instance name matches QBM settings.
SQL Error 17 or “error: 40” or “A network-related or instance-specific error occurred”	SQL instance is unreachable, wrong instance name, or blocked by firewall/network.	Confirm SQL Server instance service is installed and running. Confirm server name/instance/port settings in QBM are correct. Ask IT to allow SQL connectivity through firewall.
SQL Error 18456 or “Login failed”	SQL authentication failed (wrong user/password), or credentials were changed.	Verify QBM username/password (password is case sensitive). Confirm the SQL login exists and has access to the database. If multiple users suddenly see this: confirm server settings were not changed.
SQL Error 4060	Database name is incorrect, missing, or the login has no access to that database.	Verify the database name in QBM settings. Confirm the database exists on the server. Confirm permissions for the SQL login.
“ContractFilter mismatch…”	Client/server version mismatch (new client with old server or the opposite).	Update the server to match the client version (recommended). Or install the matching client version used by the server. After updating, restart QBM Server service.
“The remote endpoint no longer recognizes this sequence” or reliable session faults	A broken or reset session between client and server (network interruption or service restart).	Close and reopen QBM client. If repeated for many users: restart QBM Server service. Check network stability and VPN reliability.
“Could not establish connection to internet” (only if your setup requires internet checks)	Some environments check connectivity; unstable internet may cause certain connection-related prompts.	Check internet access on the client/server as required by your configuration. If your business uses VPN/cloud server access, verify the VPN/ISP link.

4) Optional: Offline Mode prompt (if enabled)

In some installations, QBM may offer Offline Mode when it detects a connectivity issue.

If you see a prompt asking to work offline, it generally means the system cannot reach the server reliably.
Offline mode is intended for temporary network outages, depending on your company’s configuration and allowed features.

5) What to collect before contacting support

Sending complete information reduces troubleshooting time significantly:

The exact error message shown in QBM.
Whether the issue affects one user or multiple users.
The server name/IP and (if applicable) port configured in QBM settings.
The database name you are trying to connect to.
The time the issue started.
Whether a server restart / service restart was attempted.

Local log file (on the client PC):
QBM stores recent warnings and messages under the current Windows user profile in:
%LOCALAPPDATA%\QBM\WarningAndInfoMessages.txt
This file keeps recent messages (typically up to 30 days). If available, attach the relevant lines to your support request.

6) Final decision checklist

If multiple users cannot connect:

Restart QBM Server Windows Service.
Restart SQL Server service (correct instance).
Check firewall/antivirus and server resources (disk/RAM).
If still failing: restart the Windows Server.

If only one user cannot connect:

Verify QBM settings on that PC (File → Data Utilities → Settings).
Confirm VPN/LAN connectivity to the server.
Restart the PC, then try again.
Share the exact error message with support and include the local log file path above.