Failed to restart redis.service: Unit not found.

This error message suggests that the Redis service may not be installed or configured correctly on your system.

To resolve this issue, you can try the following steps:

1. Check if Redis is installed on your system by running the command:

`redis-cli ping`

If Redis is installed and running, you should see the response "PONG".

2. If Redis is not installed, you can install it using your system's package manager. For example, on Ubuntu, you can run:

`sudo apt-get install redis-server`

3. If Redis is installed but the service is not running, you can start it using the command:

`sudo systemctl start redis`

4. Once the service is running, you can check its status using the command:

`sudo systemctl status redis`

If the service is running correctly, you should see the status "active (running)".

5. If you still encounter the error "Unit not found" when trying to restart the Redis service, you may need to check your system's configuration files to ensure that the service is set up correctly.

Alternatively, you can try reinstalling Redis to ensure that all necessary files and configurations are properly installed.

`sudo apt-get purge redis-server`

`sudo apt-get install redis-server`