No harm in resetting no less then 3 times in a row to force the issue.
Verify your technique for your specific Mac:
Try resetting the SMC https://support.apple.com/en-us/HT201295
Try resetting NVRAM/PRAM http://support.apple.com/kb/ht1379
Do you see all ports in the > (hold Option key) System Information>Hardware>USB
You can try running the Diagnostic/AHT http://support.apple.com/kb/HT1509
Not as specific as the in-store backbench 'Apple Service Toolkit'
If no resolve it sounds like a hardware issue
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 )
“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
Call Customer Support (800) MY–APPLE (800–692–7753)
or on line https://getsupport.apple.com/
or call AppleCare Support at 1-800-APLCARE (800-275-2273)
Get your Mac ready for service - Apple Support https://support.apple.com/en-us/HT209095