Oauth Configuration for Salesforce

I have created a oauth app in Atlassian named as ‘Fieldbuddy Integration’. I want to use this authentication method to call JIRA endpoint([https://certusportautomation.atlassian.net/rest/api/2/search](https://certusportautomation.atlassian.net/rest/api/2/search)) via Salesforce.

The problem which I am facing currently is that the oauth connection is getting authenticated for once and I am able to hit the endpoint successfully but after sometime the session is getting expired. I have put the appropriate scopes as well.

Do I need to make the app distributed or is there something missing in my configuration?

I have attached my current Salesforce setting in the attachment.