Yes, I think that the problem is in hosting, but I can't change it. That's why I think that the number of retry attempts option would solve my problem. Or if I had the ability to rescan only elements with an error.
In the options I found "Automatic retry on error" section, but I don't understand when these options are used. I set Retry count and Delay, but it doesn't help.
I checked one of my old sites with 9.7 version and have the same errors.
For another site, I solved my problem by changing ftp server from original Windows to FileZilla.
Maybe the problem is not quite the same, but I still think it would be useful if I could turn on something like an auto retry mode or set timeout of transfer operation, because when I click retry button the same files processed successfully and scanning continue.
This is not so convenient if you have 1000 files and 100 of them break with the error.
This could be a simple and quick solution, I think.