A little background about situation. I am using SQL Server 2019 Express installed on a Windows Server 2019. The thing is that at random times I can't reach SQL Server only from one specific server which is a Windows Server 2008R2 using SSMS tool.

But I am able to connect via RDP to this server at that time, server seems working fine from first view. From all other servers, workstations and locally I am able to connect to SQL during that not-working period.

I am connecting to server via hostname, ping resolves to IP seems good.

What I tried so far:

• checked maximum connections which is unlimited
• Firewall port 1433 is open
• I check if backup occurring at that time and this maybe causing the problem but backup is not the case.

Since the problem occurs at random I'm not sure how to collect constant logs such as network like from Wireshark. It feels like for now Wireshark could give me a big log file to analyze so I don't want to use this.

Is there a way to identify from logs or so on why such problem occurs during time to time? Should I be worried about Windows server 2008? Or should I check something else?