I am getting error "Could not connect to the controller" after installation of Leapwork and I am unable to start the controller service

Description

The Leapwork Controller is the central component in the Leapwork Automation Platform. The studio is depending on it to gain access to all the flows and related assets. The Controller also manages the Agents used for executing the automation flows. When a user starts the Studio the first time, it will automatically show the available Controller(s) and prompt the user to select which Controller to connect to. Before the user does this, Leapwork can't be used.

Leapwork controller is installed as a windows service and it runs in the background. Post-installation of the Leapwork software, if the user sees the below message then the user needs to check whether the controller service is up and running.

Resolution

The user can open up services on the computer where the Leapwork controller is installed to verify the service is running and can also start the service manually if it is not running. In order to check the service, the below steps are to be followed:

Go to the Start screen, and start typing the word "services." Then, click or tap the "View local services" search result.
Alternatively, Use the Run window to start Services.
Press the Win + R keys on your keyboard, to open the Run window. Then, type "services.msc" and hit Enter or press OK.
The Services app window will open.
Look for the service with the name Leapwork Controller.

5. Check the status of the service, if it is not running you can simply start the service or restart if the service acts faulted.

If the service is up and running, the user should be able to connect to the controller from the Studio computer (or from the same computer if the studio and the controller are installed on the same computer).

If the error is observed during the installation of the Leapwork controller, the below error message is shown:

Leapwork controller and agents are services that run against a specific port. These ports are used for communication with other components. The above error popup indicates that the port 9000 is already occupied.

Below is the list of default port for each component:

S. No.	Service Component	Default Port
1.	Leapwork Controller	9000
2.	Leapwork Controller API	9001
3.	Leapwork Agent	6777

There's an easy way to identify which application/service is using the port(s). Users can follow the below steps to find out the application name which is using the particular port. Please refer to the screenshot also to execute the steps.

Open the command prompt - start » run » cmd or start » All Programs » Accessories » Command Prompt.
Type netstat -aon | findstr '[port_number]'. Replace the [port_number] with the actual port number that you want to check and hit enter.
If the port is being used by any application, then that application’s detail will be shown. The number, which is shown in the last column of the list, is the PID (process ID) of that application. Make a note of the PID.
Type tasklist | findstr '[PID]'. Replace the [PID] with the number from the above step and hit enter.
You’ll be shown the application name that is using your port number.

Users will require changing the port to a different value if another application is already running on the default one as that will cause the corresponding Controller service to fail during startup. You can refer to the below article to change the installation port.

https://support.leapwork.com/hc/en-us/articles/115001170991-I-am-getting-error-Port-9000-is-already-in-use-error-during-installation-

Sometimes, there could be additional challenges while attempting a service start/restart. For example, when the service start/restart is attempted user may see below error: