Getting Server languageserver.ccls failed to start: error, when ever I open cpp file inside neovim

Question

Server languageserver.ccls failed to start: Launching server "languageserver.ccls" using command ccls failed.

I have installed coc-ccls, and I have pasted the below code inside the cocconfig file.

  {
      "languageserver": {
          "ccls": {
              "command": "ccls",
              "filetypes": [
                  "c",
                  "cpp",
                  "objc",
                  "objcpp"
              ],
              "rootPatterns": [
                  ".ccls",
                  "compile_commands.json",
                  ".vim/",
                  ".git/",
                  ".hg/"
              ],
              "initializationOptions": {
                  "cache": {
                      "directory": "/tmp/ccls"
                  }
              }
          }
      }
  }