Hi @raghavendrap,
Are you using Appium Desktop 1.8.1 or Appium Server 1.8.1? Unfortunately, the version numbers don’t line up.
If you downloaded an installer to get Appium, it’s probably Appium Desktop, so I recommend getting Appium Desktop 1.6.3: Release 1.6.3 · appium/appium-desktop · GitHub
If you got Appium from npm, then you can verify your version by running appium -v from he command line or use npm install -g appium@1.8.1 to install it.
Check here for some more common troubleshooting tips:
Hope this helps,
Chris