Hi @kks8589 ,
Welcome to Microsoft Q&A platform and thanks for your query.
You issue seems to similar to this: SFTP Connection Issue
Since your test connections are successful and failing only when you ran pipeline, it could be a networking issue on your SHIR hosted machine. Please validate your SHIR hosted machine network settings to allow connection to your sink SFTP server.
Helpful info: Copy operation determining which IR to use
Hope this helps. Let us know if you have further query.
Thanks you
Looking forward to your confirmation.