I was asked this and then the error was back.
On my second device, a laptop, it works flawlessly.
2025-03-24 13:19:36 [ERROR] /Users/patricklux/Pictures/Arbeitsfoto Studio/20250324 GERSAM/jpg edited/20250324-GERSAM-Hamburg-patricklux.de_1.JPG SFTP Net::SFTP::StatusException (4, "failure")
2025-03-24 13:19:38 [ERROR] /Users/patricklux/Pictures/Arbeitsfoto Studio/20250324 GERSAM/jpg edited/20250324-GERSAM-Hamburg-patricklux.de_2.JPG SFTP fingerprint 0a:49:57:c0:d6:84:fc:2f:f1:76:cf:19:58:17:c4:88 is unknown for "ftp.picdrop.com,2a05:d014:1a28:b400:598c:7437:b892:e454"