@Sharma, Paridhi With respect to the bot that is your QnAMaker KB the reason for no response could be an issue with the app service which might need an restart but it also needs to be investigated as to why the app or bot service failed to respond if there is no change.
The KB details from the portal should be available to edit unless the user is not having access to edit them. Does this scenario happen every time you want to edit your KB? Could you please try using the REST API to make a similar edit to your KB?