Hi,
The log shows:
0953.455 (3) PHP event: code E_WARNING: Error while sending QUERY packet. PID=23339 (line 2007, wp-includes/wp-db.php)
The most likely cause is that the database server drops the connection to WordPress after a set amount of time, and as a result UpdraftPlus isn’t able to update the database’s record of backup progress. You could avoid that by adding this to your wp-config.php, which causes UpdraftPlus to kill itself after 90 seconds (which appears to be the time after which the errors start) – when it resumes, it then will get another 90 seconds (and will continue until it completes):
define(‘UPDRAFTPLUS_SET_TIME_LIMIT’, 90);
Best wishes,
Bryle