Intermittent .NET Assembly SSL Data connection timeout

Hello:

A customer is having trouble with our application. They are having intermittent data connection timeouts, and I am trying to troubleshoot. I have not been able to consistently recreate the issue locally and am trying to narrow down the cause. Two thoughts are that part of the passive dynamic port range is not open in the firewall or the server is slow and is just often taking a long time.

One thing I noticed in the logs was the timeouts were different. I'm using WinSCP.NET 5.19.1 via the .NET Assembly.

First step: I am wondering if it is possible to control the following 10 second data timeout value for a passive FTPS Implicit TLS/SSL connection because it does not seem to match the setting:

425 SSL Data connection not received within 10 sec. on port 37144

I have looked through what I was able to find in the documentation, and I have set the below. I didn't see any other rawsettings that seemed to apply:
Note: I used TimeoutInMilliseconds, but I assume if I used Timeout it would work the same.

However, the above only seems to control the timeout below:
However the above "not received within 10 sec" seems unaffected. The log timing matches indicating just slightly more than 10 seconds have elapsed:
Attached includes a failure as well as a follow up (5 mins later) few successes and finally a failure.

Being a production site, I have not just tried to load the latest version because they want some confidence in fixing the problem.

Any suggestions?

Thanks!

The error comes from the server. It's a server-side timeout.

🤦‍♂️. Thanks for the quick reply!