Rebooting will redefine port definition as well as resetting NVRAM/PRAM http://support.apple.com/kb/ht1379
If no resolve—Call Customer Support (800) MY–APPLE (800–692–7753)
Mac notebook, contact us and we'll send you a box you can use to ship it to an Apple Repair Center. We'll return your repaired product to you as quickly as possible. Depending on where you get service, you might be able to check the status of your repair online. Start a service request https://support.apple.com/mac/repair/service
In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment
Make an appointment for a "hardware issue"—
https://www.apple.com/retail/geniusbar/
Outside the USA
https://locate.apple.com/country
From iOS device using the app to make a online Genius Bar appointment is easy:
https://itunes.apple.com/us/app/apple-support/id1130498044?mt=8
(note: due to the temporary closure of Apple Stores and the staggered reopening there may be some delays.
ref: https://www.apple.com/shop/browse/store/temporary_closures )
