A remote copy between thor clusters can often report a comment in the logs:
No matching drop zone path to file path: ...
Drop zones are not being used for this remote copy so it can be confusing.
And also there is this msg:
Unable to find machine for 18.104.22.168
Use pull operation because 22.214.171.124 doesn't appear to have an ftslave
But there is an ftslave present, it is just that machine 126.96.36.199 is not in the DZ list so it fails the check for an ftslave.