2 speakers of 6 speakers not working

hi all
2 of my 6 speakers ( the port rear and port mid) were not working. Then I had the other 4 speakers and 1 sub cranking for a while then the 2 speakers suddenly worked. Did the bass vibrate something into place? I guess I have a wiring issue? Or is it possibly an issue with my amp? Any idea on how to trouble shoot?
Thanks

Mid and rear are most likely 1 channel. If both cut out I would start where they connect to the receiver/ amp. Id guess a loose connection.

Thanks the issue was with the amp. One of the channels was shot