Thank you for the log file. I don't see any FTP errors in your log file. However I do see errors accessing Photo Mechanic's cache folder that could be the cause of the FTP problem, because the cache folder is where Photo Mechanic stores a copy of the images that you are uploading.
I'd first check to make sure you have plenty of available disk space. If you do then quit Photo Mechanic and delete Photo Mechanic's cache folder to see if that fixes the FTP problem. On macOS, the easiest way to get to the "cache" folder without PM running is to use the "Go to Folder..." command on the Finder's "Go" menu and enter:
~/Library/Caches/Photo Mechanic
Delete the "cache" folder and then run Photo Mechanic and try another FTP upload. I'd like another PM_log.zip file from you if the problem persists.
HTH,
Jerry