The stability of the domain name resolution server is really important

Last night, I found that the main site Xingfu Bar was inaccessible, but other domain names bound to this space were accessible (including this server).
The primary domain name uses the site5 DNS server, and other domain names use godaddy or other domain name resolution servers.
After that, send tips to site5.
Fortunately, site5's service was worth its price and the problem was solved within 2 hours.
Appendix: Several stable domain name resolution servers that support domain name forwarding