Hello,
It's quite an unusual situation you're facing. If the issue is intermittent and only occurs during the first connection attempt, it can be challenging to pinpoint the exact cause. But capturing network traces and reviewing server logs during the time of the issue might provide more clues.
Are you experiencing this issue with other devices as well? Investigating whether the problem is specific to your PC or related to server-side factors could provide more insights.
Have you tried some basic troubleshooting steps? For instance, measure the response time when ping respond, sometimes high latency could cause delays in communication.
Does DNS resolve correctly , and is it using the correct DNS server? DNS resolution issues could cause delays in connecting.
Another recommendation is to clear the ARP cache on both your PC and the server. This could help refresh the ARP table and improve communication.
Thank you