can ping server but can't ping or join domain (DNS issue ?)

Like you can see in the title, I have a server with a LAN domain (+ DHCP/DNS, AD, FileServer). After a blackout, we had to reset our routeur and APs and since then, I can't access the domain with the clients computers.

DNS error :

DNS name doesn't exist

error code 0x0000232B RCODE_NAME_ERROR

resquest's SRV target : _ldap._tcp.dc._msdcs."domain".lan

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something like "No delegate zone for child zone"

The server's IP configuration is :

IP : 192.168.1.2

Mask : 255.255.255.0

Gateway : 192.168.1.1

Additionnal information :

The DNS server has the same IP address as the server (192.168.1.2) and is set manually on each client.

From the clients I can ping the server and access the shared folders.

I've seen everywhere that I have got to create a PTR on reverse lookup zone with the DNS IP, which I already have.

Plus : IPv6 is desactivated

Tests done :

nslookup with FQDN --> Serveur : Unknown and Address 192.168.1.2

net use on shared folder --> OK

ping FQDN from client --> can't find host

replace PTR on DNS and restart service

ping client from server --> can't reach

I checked my DNS config again and again. Maybe the problem comes from my router ?

I'm getting lost and if you have an idea I'll gladly hear it

Q.