In my specific case i wanted to transfer 18TB of data.
After starting the process i got following Status UI:
After a day it broke with an error:
Error Details:
rsync: connection unexpectedly closed (187257437 bytes received so far) [Receiver]
rsync error: error in rsync protocol data stream (code 12) at io.c(228) [Receiver=3.2.5]
My solution was to disable the option "Delay Updates" it's help text says "Set to save the temporary file from each updated file to a holding directory until the end of the transfer when all transferred files are renamed into place." I assumed it is to much for 18TB of data.
I don't know if the problem was the size but it solved the problem!