Thanks very much for your advice. I found 3 very large log files, which I deleted or reduced, and I no longer get those warnings.
However, every backup is still failing, and the logs still say “The backup attempt has finished, apparently unsuccessfully” and “413 Request Entity Too Large”.
The latest log is at https://www.dropbox.com/s/w91cpqon4snrplo/Updraft_log_31Mar20.txt?dl=0 .
Do you have any other suggestions?
