Hello,
If you can still ping the server by IP but reverse lookup is failing, first confirm whether the DNS Server service is actually stopped or crashing:
Get-Service DNS Get-WinEvent -LogName "DNS Server" -MaxEvents 30
Also check Event Viewer > Windows Logs > Application/System around the exact crash time for DNS, DNS-Server-Service, Service Control Manager, or application-crash events. If the DNS service is stopped, try starting it with Start-Service DNS and record any error rather than repeatedly restarting the server.
If forward DNS works but only reverse lookup fails, also verify that the appropriate Reverse Lookup Zone and PTR records still exist in DNS Manager. Network connectivity by IP only confirms that IP routing is working; it does not confirm that the DNS service or reverse zone is healthy.
Please share the relevant DNS/Event Viewer error or Event ID from the time of the failure, and we can narrow down the cause.