scp from remote to remote does not work if not using -3

I mean to copy files from one remote server to another. If using scp -3, command succeeds (I have remote1 and remote2 in my ~/.ssh/config) $ scp -p -3 remote1:dir1/file1 remote2:dir2/ but when not using -3, it fails $ scp -p remote1:dir1/file1 remote2:dir2/ ssh: Could not resolve hostname remote2: Temporary failure in name resolution lost connection **Why is that?** As I understand from man scp and other sources, -3 is not mandatory, but simply -3 Copies between two remote hosts are transferred through the local host. Without this option the data is copied directly between the two remote hosts. I am using msys2, I wouldn't know if that makes any difference.