"An error occurred, Unable to connect to Jenkins"

After installing Jenkins on AWS Ubuntu. Login on browser and Click on Install plugins I’m getting “An error occurred, Unable to connect to Jenkins” . So now what I do to solve this problem ?

You’ll need to provide much more detail before others will be able to assist you or will be persuaded to assist you. Good guidelines on the types of information that need to be provided are included in the “How to report a issue” page.

Please note that I am not recommending that you open an issue in the Jenkins issue tracker. I am recommending that you look at the list of details included in that page, collect those details, and use those details to resolve your issue. If you can’t resolve the issue, then post those details here.

Posting an image of “An error occurred” is not enough information to persuade others to help you.

I am getting the same error, it seems the Issue is still not resolved.

I got the same issue but resolve after restarting