While configuring Manage Metadata Service (MMS) Application in a newly created web application I got the error as “The Managed Metadata Service or Connection is currently not available. The Application Pool or Managed Metadata Web Service may not have been started. Please Contact your Administrator.” It long time for me to figure out root cause of this issue.
While creating Web Application I have not selected any application services apart from Access service 2010 service.
Enable service application “MMS Application” for newly created web application by following the below steps.
Step1: Log on to application server with super admin account and open Central Admin.
Application Management -> Configure Service Application associations
Step 2: If you notice I can’t see MMS application not listed for SharePoint – 12345 web application
Step 3: Click on “Custom” hyper link to add the MMS application to web application
Step 4: Once we select the MMS application it will as below
Step 5: As soon as this change has been completed I can see all the term stores and terms.
Other possible issues and solutions can be found in below MSDN article. Hope this helps enjoy administration in SharePoint 2013.!!!