FTP error

Hello!
After moving three sites to another server/host the FTP upload is not working anymore. All tests fail in writing into the file (which definitely exists and the path is correct).

When running a backup, though, the log does not list the new credentials, UpdraftPlus seemingly tries to log in into the old account!!?
Although the new log-in data is saved in the settingss.
Really mysterious! Why does it not overwrite it?
Thanks for a solution.

The page I need help with: [log in to see the link]