Diagnostic
The embedded DNS of the USM is faulty. The DNS resolution fails, or the resolved address is incorrect.
Possible causes
1. The naming authority pointer (NAPTR) is incorrectly configured.
2. The SRV record is incorrectly configured.
3. The resource record (DNSRSC) is incorrectly configured.
Troubleshooting procedure
Orderly check the configuration information of the NAPTR, SRV record and DNSRSC.