The “550 I can only retrieve regular files” coming from PureFTPd before the connection drop/timeout is probably important. Resolving that will most likely resolve the reconnection issue.
From a web search, “550 I can only retrieve regular files” from PureFTPd may indicate one of the following:
[ul][li]Opus is trying to download a directory as if it was a file.
Easy way to find out: Edit the FTP bookmark and, on the Display tab, under Log, turn on Enable debug. The log will then include the commands Opus sends to the server in addition to the responses it gets back, and you’ll be able to see which file Opus is requesting, if any.
If you see Opus trying to “GET” a directory instead of “LIST” or “DIR” it, then that probably explains what is happening.
This can be the result of Opus incorrectly guessing whether a link on the server is a file or a folder. FTP does not provide a reliable way to find this out, so clients have to guess sometimes, and things will become confused if the guess is wrong.
You can override the guesswork by editing the FTP bookmark and, in the middle of the Display tab, changing Treat unknown link as… to “folders”. That may fix things on its own, after restarting Opus.
[li]Trying to read a directory listing that cannot be read due to permissions on the server.
Easy to test using another FTP client and going to the same /web/wp-content/uploads directory.
[li]Possibly, incorrect MLST/LIST settings for the server within the FTP bookmark’s Misc tab, although that should not be a factor with PureFTPd as long as you haven’t changed the defaults.[/li][/ul]