phonegap server error

[piyush99755]

Hello.
I have been trying to use Phonegap serve command but it is throwing me some error and also I am unable to access the app through my running server.
Would someone help me please?

TypeError: Cannot read property 'then' of undefined
at AppCommand.run (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\lib\phonegap\serve.js:87:43)
at PhoneGap. (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\lib\phonegap\util\command.js:28:25)
at CLI.module.exports (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\lib\cli\serve.js:36:14)
at CLI.module.exports [as argv] (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\lib\cli\argv.js:111:17)
at runPhoneGapCommand (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\bin\phonegap.js:46:9)
at Object. (C:\Users\Piyush\AppData\Roaming\npm\node_modules\phonegap\bin\phonegap.js:38:5)
at Module._compile (internal/modules/cjs/loader.js:959:30)
at Object.Module._extensions..js (internal/modules/cjs/loader.js:995:10)
at Module.load (internal/modules/cjs/loader.js:815:32)
at Function.Module._load (internal/modules/cjs/loader.js:727:14)