Hi Ganesh,
Since you have mentioned, only Aha app is getting stuck, I guess your internet speed is good as other streaming app are fine. So, it could be problem with the Aha app, may be a fresh installation can help you, here are the steps you can try
Uninstall the Aha app in your LG Smart TV.
Log-in to your Aha account either with mobile app or web browser (not in the TV).
Navigate to https://www.aha.video/account/devices and remove clear all the instance of lgwebostv and any other instance that you think are not necessary.
Re-install the app in you LG Smart TV.
Link the account and hope it resolves the issue.
Fallowing these steps helped me resolve another issue for me, previously.