A chunk of concrete fell off the corner of my house

[Frugal Lizard]

Not a huge chunk but big enough piece of concrete at the top corner just under the brick.
Can I "glue" it back on and seal it up well enough to backfill over it?
I think I know why this happened and have fixed the issues.

I'd post picks but can't seem to get it to work.

[Drifterrider]

If you mean mortar, putting it back won't do anything except hid the hole (space).  You can repoint (put in new mortar).  Lots of DIY stuff on you tube.

[Reynolds531]

Check for a leak above before fixing.