Cannot verify client 3000
For my case,I got this error after selecting "Generic iOS Device" when archiving, however i plugged in my iPhone and selected it, then archived, I got no errors this time.(I also cleaned both Shift+cmd+k and Shift+alt+cmd+k before archiving)
I encountered the same issue the first time I tried to submit to app store with the target on my device.
What worked for me:
I retried a couple of minutes later without changing a thing and everything went smooth.
This is temporary apple server bug. Try it again OR Retry after some time it will fix the problem.Thanks