I thought it was a bit odd that a brand new UniFi US-8-60W switch, purchased on Amazon, had some scotch tape holding the outer box to the inner box. I ran adoption from Chrome but it never completed. I SSH’d into the switch. The fact that I was able to get in with the default “ubnt” username and password confirmed that adoption had not completed.
The set-inform had filled in the correct URL, but the Status showed a Decrypt Error:
This 7-year-old post explains the problem:
It seems the AP was adopted by another controller previously. try ‘set-default’ before you do set-inform.
set-default from the command line. After that, I was able to adopt the switch from Chrome.