Encountering the error message "Connection could not be established to the host" typically indicates difficulties in connecting to the designated target machine or host. Several factors may contribute to this problem.

1. Incorrect IP address entry for the target machine.

2. Unreachable state of the target host.

3. Absence of the Vembu Integration Service on the target host.

4. Inactivity of the Vembu Integration Service on the added target host.

To address this connectivity issue, follow the steps outlined below:

1. Check Host Reachability:

   Ensure that the target host is reachable from the source. Verify the accuracy of the IP address entry.

2. Verify BDRSuiteIntegrationService (BIS) Availability:

   a. Access the Control Panel on the Windows host machine.

   b. Navigate to the 'Programs' section and select 'Programs and Features.'

   c. Look for the presence of the VembuIntegrationService (BIS) agent.

3. Confirm BDRSuiteIntegrationService (BIS) Status:

   a. Open the 'Run' dialog and type 'services.msc.'

   b. Locate and inspect the status of 'VembuIntegrationService' [up to v52] or 'BDRSuite Delegation Service' [from v53].

   c. If the service is inactive, manually initiate it. If disabled, adjust the Startup type to 'Automatic' via service properties.

4. Check Port 42005 (BIS) or BDRSuite Delegation Service Port (BDS):

   a. Access the Control Panel on the host machine and select 'System and Security.'

   b. Choose 'Windows Firewall' and click 'Advanced settings.'

   c. Navigate to 'Inbound Rules' and locate the 'VembuIntegrationServicePort' [up to v52] or 'BDRSuite Delegation ServicePort' [from v53].

   d. If the port is disabled or blocked, enable it by:

      i. Right-clicking and selecting 'Properties,' then choosing "Allow the connection."

   e. If the port is absent, manually add it to the firewall:

      i. Click 'New Rule,' choose 'Port,' and proceed.

      ii. Select TCP port and specify "42005," then continue.

      iii. Allow the connection and apply the rule for Domain, Private, and Public profiles.

      iv. Name the rule as “VembuIntegrationService.exe” and finalize the addition.

5. Validation:

  Confirm the presence of the newly added rule in the 'Inbound Rules' section of the Windows Firewall.