When Jenkins tries to open connection to the SSH agent it uses the command "cd "D:\Jenkins" && java -jar remoting.jar -workDir D:\Jenkins -jar-cache D:\Jenkins/remoting/jarCache"

If the working folder is not in C drive, the cd command will not work, as it needs to be:

d:

cd "D:\Jenkins"

instead of just cd "D:\Jenkins"

[08/09/21 10:22:24] [SSH] Checking java version of java
[08/09/21 10:22:24] [SSH] java -version returned 1.8.0_301.
[08/09/21 10:22:24] [SSH] Starting sftp client.
[08/09/21 10:22:24] [SSH] Copying latest remoting.jar...
Source agent hash is *************. Installed agent hash is *************
Verified agent jar. No update is necessary.
Expanded the channel window size to 4MB
[08/09/21 10:22:24] [SSH] Starting agent process: cd "D:\Jenkins" && java -jar remoting.jar -workDir D:\Jenkins -jar-cache D:\Jenkins/remoting/jarCache
Error: Unable to access jarfile remoting.jar
Agent JVM has terminated. Exit code=1
[08/09/21 10:22:24] Launch failed - cleaning up connection
[08/09/21 10:22:24] [SSH] Connection closed.