Text disappears when exporting as single asset to .png

[defaultks1pd49kn25m]

What I want (left) versus what I get (right):

Things I've tried already:

• convert text to outline
• ensure text is on the top layer
• confirmed overprint is not set

Thanks for any help. 

[Monika Gause]

Exactly how do you export?

Is the text on a printable layer?

[Ton Frederiks]

Is all the artwork within the Artboard? Do you select use Artboards when exporting?