RE: DNS Issue with PC6248
0.us.pool.ntp.org will resolve to 4 random IPs that are in the Public NTP pool. I suspect the switch is expecting one IP address for the configuration line sntp server 0.us.pool.ntp.org and can't handle the multiple IP addresses that are returned. You can probably confirm by pointing to a FQDN NTP time server and see if that resolves the issue. Feel free to test using one of mine: ntp0.intrax.com (126.96.36.199), which is a stratum 1 in the Public NTP pool. You probably don't want to leave it like that long-term however because I'm on the east coast and you probably want one closer to Arizona.
I have a different switch than you do so the lines below may not be applicable. For my switch, I also have these configuration lines in my switch:
- clock source sntp
- sntp server A.B.C.D poll