Why isn't my Paladin resurrecting my guard droids?

[DGDobrev]

Paladin hero is AMELIE, PALADIN class.

Paladin unit is the gold-armored Knight from KBTL. He resurrects only living organisms of level 1, 2, 3, and 4.

The droids have the ability MECHANICAL, meaning they are mechanical objects. This means that they cannot be resurrected, do not succumb to mind effects, and have high poison resistance. Read the ability description carefully.

For the same reason, the Thorns are PLANTS. Plants cannot be resurrected.