Nameserver Troubleshooting

Hi, I need some assistance troubleshooting my nameservers.

I recently leased a new Dedicated Server from OVH running Almalinux 9 to replace an older one running Centos 7. I documented the earlier installation and essentially repeated the steps (as closely as possible) on the new server, Using WHM, the default nameserver for Centos 7 was BIND. On Almalinux the default is PowerDNS, so that's what I originally chose using the Primary Resolver address provided by OVH. However, I could not get a response from any of my domains, even days after I updated their nameserver records at the registrar.

I checked intoDNS.com, which reports that "one or more of my nameservers did not respond". I checked that port 53 was open and disabled ConfigServer Firewall. Everything I compare on my old and new servers was the same, but I still could not get a response. The only differences I found during installation were under DNS Zone Manager. On Almalinux, three domains were created automatically. One is the Reverse DNS Address, which has dns10.ovh.ca and ns10.ovh.ca recorded as its nameservers. The other domains are those nameservers: dns10.ovh.ca and ns10.ovh.ca.

I tried changing the nameserver to BIND, but this did not not help. It did however produce a strange result. If I enter the Reverse DNS of my Centos server in my browser, I get a "Sorry" defaultwebpage.cgi, which I would expect because it's not a real domain. When I had the Almalinux nameserver set to PowerDNS, the same thing would happen with its Reverse DNS IP. But when I changed to BIND, the browser now opens the home page for one of my accounts on the new server. I have several accounts set up, so I don't know why or how it is picking that one in particular.

I'm a programmer, not a server administrator, and don't know a lot about this material, but hopefully someone can give me a starting point and I can research from there.