FileSync local endpoint offline

Hi,
i have 3 servers (one of them with Windows Server 2012 R2 and 2 with Windows Server 2019) and i use Azure FileSync to sync files between them.
Since a few days i have a problem, the 2012 R2 server is appearing offline in the azure portal (it shows "no activity"). I tried the Test-StorageSyncNetworkConnectivity cmdlet and it fails with the following message:

Discovery service connectivity result:  
        Result: Success  
        HostUri: unknown  
        HostIPv4Addr: Fail. DNS name does not exist. Resolution through GetAddrInfo failed with error: 11001  
        HostIPv6Addr: Fail. DNS name does not exist. Resolution through GetAddrInfo failed with error: 11001  
  
Management service connectivity result:  
        Result: Fail. Failed to run test  
        HostUri: unknown  
        HostIPv4Addr: Fail. DNS name does not exist. Resolution through GetAddrInfo failed with error: 11001  
        HostIPv6Addr: Fail. DNS name does not exist. Resolution through GetAddrInfo failed with error: 11001  
        HostNetworkLatency [min,avg,max]: Network Latency Request Failed.  
  
Monitoring service connectivity result:  
        Result: No response from monitoring agent process.  
        HostUri: unknown  
        HostIPsAddr: IPv4 and Ipv6 addresses do not exist  
  
ServerEndpoint: faf66731-1e22-47eb-93eb-b8d3331f0de2  
        SyncServiceResult:  
        SyncServiceHostUri:  
        SyncServiceHostIPsAddr: IPv4 and Ipv6 addresses do not exist  
        SyncServiceHostNetworkLatency: Request Failed.  
  
  
ServerEndpoint: 80f3bb96-463b-4f86-9e26-8dcf0c92f915  
        SyncServiceResult:  
        SyncServiceHostUri:  
        SyncServiceHostIPsAddr: IPv4 and Ipv6 addresses do not exist  
        SyncServiceHostNetworkLatency: Request Failed.  
  
  
ServerEndpoint: b9a874b4-7acd-4174-b5e8-26ac23c84c7e  
        SyncServiceResult:  
        SyncServiceHostUri:  
        SyncServiceHostIPsAddr: IPv4 and Ipv6 addresses do not exist  
        SyncServiceHostNetworkLatency: Request Failed.  
  
  
Remediation Steps  
For Azure File Sync to work correctly, you will need to configure your servers to communicate with multiple Azure servic  
es  
Refer the following public document for details on proxy settings or firewall settings for Azure File Sync - https://aka  
.ms/AFS/ProxyAndFirewall  
If you have configured a private endpoint refer the following public document for configuring private endpoint for Azure  
 File Sync - https://aka.ms/AFS/PrivateEndpoint  
  
  
  
                                          NetworkTestPassed Report  
                                          ----------------- ------  
                                                      False ...  

The problem seems to be DNS related, but i tried the Test-NetConnection -ComputerName <remote-host> -Port 443 cmdlet with the correct URLs (taken from https://video2.skills-academy.com/it-it/azure/storage/file-sync/file-sync-firewall-and-proxy#test-network-connectivity-to-service-endpoints) and all the endpoints seems to be working fine (the ping is failing but i think that is regular behavior. E.g.:

PS C:\Program Files\Azure\StorageSyncAgent> Test-NetConnection -ComputerName tm-kailani7.one.microsoft.com -Port 443  
AVVISO: Ping to tm-kailani7.one.microsoft.com failed -- Status: TimedOut  
ComputerName           : tm-kailani7.one.microsoft.com  
RemoteAddress          : 20.38.85.153  
RemotePort             : 443  
InterfaceAlias         : Ethernet 2  
SourceAddress          : 192.168.0.185  
PingSucceeded          : False  
PingReplyDetails (RTT) : 0 ms  
TcpTestSucceeded       : True  

I also tried the FileSyncErrorsReport.ps1 but even that doesn't give me any error:

AVVISO: There are no file sync errors to report. Either the last completed sync session did not have per-item errors or  
 the ItemResults event log on the server wrapped due to too many per-item errors and the event log no longer contains  
errors for this sync group. To learn more, see the Azure File Sync troubleshooting documentation:  
https://aka.ms/AFS/FileSyncErrorReport  

I think the problem lies with the fact that the AzureStorageSyncMonitor.exe process is not running and if i try to run it manually it just closes itself after a few seconds.
I've got no event ID 9301 (specified here: https://video2.skills-academy.com/it-it/azure/storage/file-sync/file-sync-troubleshoot?tabs=portal1%2Cazure-portal#server-endpoint-health) and by searching in the other folder of eventvwr i could only find the event 4104 which shows me some error dated to the last time the server has reached the Azure endpoint:

Querying for new jobs failed.  
  
HttpErrorCode: 0x80C8700C  
InternalErrorCode: 0x80C80300  

Any help would be greatly appreciated, thank you.