SUMMARY STEPS TO REPRODUCE 1. Create a new sftp network connection 2. At first, everything will work fine 3. If the respective Dolphin window is left open for a few minutes and then you return to it, no operations will ever work again on the same connection, returning "Internal Error" or "File cannot be copied: Retry", with "Retry" never working again. The only way to fix it is to browse to "Network connections" again, and then again clicking on the respective connection. SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: 5.0.0-37-generic (available in About System) KDE Plasma Version: 5.17.4 KDE Frameworks Version: 5.64.0 Qt Version: ADDITIONAL INFORMATION
Correction: it is impossible to fix the connection once this has occured; it has to be recreated.
*** This bug has been marked as a duplicate of bug 413294 ***