Cannot create a project due to unknown error

[sriranjitha Vasudevan]

We are unable to create any new projects and error's with "Hmm we couldn't create a project due to an unknown error " . 

Here are some logs : 

2019-08-06 19:27:21,013 http-nio-8081-exec-607 ERROR  1167x835759x1 1tdaxl8 12.97.180.36,10.10.12.217 /rest/project-templates/1.0/templates [c.a.s.internal.project.ServiceDeskProjectConfigurator] Error automatically creating a linked Confluence Knowledge Base space upon project creation: sd.applinks.error.missing : 'Can't connect to Confluence because the application link is missing. Check the Confluence settings in Application Links.'
2019-08-06 19:27:21,013 http-nio-8081-exec-607 ERROR 1167x835759x1 1tdaxl8 12.97.180.36,10.10.12.217 /rest/project-templates/1.0/templates [c.a.jira.project.ProjectCreateRegistrarImpl] The handler with id com.atlassian.greenhopper.project.PermissionSchemeProjectCreateHandlerImpl.ProjectCreateHandler threw an exception while handling a notification about a project being created
org.eclipse.gemini.blueprint.service.importer.ServiceProxyDestroyedException: service proxy has been destroyed12:51 PM'Can't connect to Confluence because the application link is missing. Check the Confluence settings in Application Links.'

How do we go about resolving this issue? 

Thanks!! 

[Nic Brough -Adaptavist-]

Log into your Jira as an admin, go to admin -> application links and create or fix the link to Confluence.