SFTP Timeouts occurring frequently with larger files (> 300KB)

Hello, We are facing an issue when using UltimateFTP (v6.8) with an SFTP connection. We find that we receive a timeout when attempting to upload files larger than 300KB. We have gone as far as to increase the Timeout property of the sftp client object to 5 minutes, but the issue persists. Below is a sample stack trace of the exception thrown when the timeout occurs: Sftp: 1, Thread Id: 0 [10/12/2022 16:09:22.64] Information - Info: Connecting to 10.9.79.247:22 - Sftp v6.8.40.4155 (Production version). Sftp: 1, Thread Id: 0 [10/12/2022 16:09:23.67] Error - Info: ComponentPro.Net.ProxySocketException: An operation timed out. at ComponentPro.Net.ProxySocket.c_JND(IAsyncResult c_UFD) at ComponentPro.Net.Sftp.c_K4E(String c_ROA, Int32 c_PKD, SecureShellConfig c_LJB, AsyncOperation c_M) Note that the issue does not occur when using regular FTP, and that we have tried testing a file upload against the same SFTP server with a different client (i.e. WinSCP) which was successful. Are there any specific diagnostic measures you recommend? Efforts to reproduce the issue on a development/test server have not been successful, and only occur on the production site. Thanks! Stephane