Here is the description of the bug along with a resolution:

Cause

The "CMon Server Administration" desktop application (which can be launched from the Start Menu) incorrectly updates the service configuration and application settings in the database, preventing agents from being able to reconnect to the Management Server.

If you open the "CMon Server Administration" desktop application, click on Save, and then restart the "Management Server" windows service, it will prevent agents from reconnecting.

Resolution

1. system.serviceModel.services.config

The desktop application incorrectly adds an extra path to the baseAddress in system.serviceModel.services.config.

For example, in C:\Program Files (x86)\NovaStor\NovaBACKUP Central Management Console\Service\system.serviceModel.services.config

<add baseAddress="net.tcp://localhost:4502/AgentService" />

If you manually modify the file, remove the last segment /AgentService, and restart the "Management Server" windows service, the agents will start to reconnect successfully.

For example, this is the correct value for the baseAddress:

<add baseAddress="net.tcp://localhost:4502/" />

You will need to fix the configuration file in at least two places.

2. ManagementServer Database

The desktop application removes the hostname / IP Address from the HubConnectionUrl value in the application_settings database table.

For example, the SettingValue for the HubConnectionUrl SettingName should be

http://<hostname or IP Address>:80/ManagementServer/signalr

Using SQL Server Management Studio, right-click the the application_settings table in the ManagementServer database and choose "Edit Top 200 Rows".