Is this the same issue we are already discussing here, or a different one?
If it's a different one, we would need more information.
If it's the same one (you occasionally get "No connection could be made because the target machine actively refused it" errors while trying to connect to a server), it indicates an issue at the TCP layer. However, you are basically saying that you need know, but you are not allowed to investigate. Unfortunately, we really can't help you with that - you will have to get in touch with someone who can investigate.
Servee team is updating us there is no issue sr their end.
What does this actually mean? Does this imply that they are not aware of any failed connection attempts by your SFTP client? That would mean your packets are not even reaching there server, suggesting the issue is either in the client or along the way. But I would rather not speculate based on vague statements. If they could clarify what they mean by "no issues at their end", perhaps we might get somewhere.
Also, what about the client-side team? Can they investigate?