SSHException Channel was closed intermittent behavior

We are connecting to a client SFTP and prior to this week had nothing but successful transactions.
We are now experiencing intermittent exceptions. We are calling this functionality from an Azure function, and the files are streamed from Azure storage, but i don't believe that has any impact on the issue.
I have tried both synchronous and asynchronous methods and had success locally, and on majority of live test cases, but when it fails, I don't have an idea of what the problem may be. Any thoughts would be much appreciated.

My code is below:

sftpClient.Connect();
var uploadPath = $"{sftpFolder}/{fileName}";
sftpClient.UploadFile(stream, uploadPath);
sftpClient.Disconnect();

Alternatively, I tried instead:

sftpClient.Connect();
var uploadPath = $"{sftpFolder}/{fileName}";
var returnVal = sftpClient.BeginUploadFile(stream, uploadPath, new AsyncCallback(x => FileTransferred(x, log, fileName, uploadPath)));

報告されている Connect()、UploadFile()、BeginUploadFile() の呼び出しから着手し、Azure Function での断続的な失敗と、ローカルでの成功する実行を比較してください。SSHException のコンテキスト全体と、接続または転送の条件を記録してください。完了条件は、断続的なチャネル切断の再現可能な原因を特定し、修正を文書化または検証することです。