Scheduled backup won't run, exclude doens't work

Hi,

Problem one: Daily backup
I have a problem with the daily scheduled backup. As I set the time right (lets say 01:00 AM), it runs no backup at all.
The backup starts running when I login to my back-end, also then it wil send out an notification e-mail. If I don’t login, no backup will be made.
The backup look as follow:

3 backups completed Size Type Actions
September 11, 2015 – 7:11 am 24 MB Database and Files Download | Delete
September 10, 2015 – 3:38 pm 24 MB Database and Files Download | Delete
September 9, 2015 – 7:42 am 24 MB Database and Files Download | Delete

Problem two: Exclude
When I back-up my website I get the following error:

Trying to get property of non-object, /var/www/vhosts/44/192602/webspace/httpdocs/switchtest.nl/weclines/wp-content/plugins/root-relative-urls/sb_root_relative_urls.php, 97, Creating default object from empty value, /var/www/vhosts/44/192602/webspace/httpdocs/switchtest.nl/weclines/wp-content/plugins/root-relative-urls/sb_root_relative_urls.php, 97, Undefined property: stdClass::$post_excerpt, /var/www/vhosts/44/192602/webspace/httpdocs/switchtest.nl/weclines/wp-content/plugins/root-relative-urls/sb_root_relative_urls.php, 98

Now I see that the error is about a plugin that is not that important to backup, so I thought lets exclude it.

/wp-content/backupwordpress-32f2b3290d-backups/ Default rule
/wp-content/plugins/root-relative-urls/ Stop excluding

But with the exclude shown above the error still comes up every time.

I hope you can help me!

Kind regards,

Mark Haveman

https://wordpress.org/plugins/backupwordpress/