Empty CSV, preview data OK?

Hello, first of all, thanks for this great tool!

I have just scraped one page of a big website, just to test the system.

This is my sitemap
{"_id":"taxi-gevonden","startUrl":["https://taxigevonden.nl/veghel/taxi-uden-en-veghel-drive-we-go-bv/892336"],"selectors":[{"id":"bedrijf","type":"SelectorText","parentSelectors":["_root"],"selector":"h1[itemprop='name']","multiple":false,"regex":"","delay":0},{"id":"plaatsnaam","type":"SelectorText","parentSelectors":["_root"],"selector":"span[itemprop='addressLocality']","multiple":false,"regex":"","delay":0},{"id":"postcode","type":"SelectorText","parentSelectors":["_root"],"selector":"span[itemprop='postalCode']","multiple":false,"regex":"","delay":0},{"id":"website","type":"SelectorLink","parentSelectors":["_root"],"selector":"p a[data-target]","multiple":false,"delay":0},{"id":"link_naar_telnummer","type":"SelectorLink","parentSelectors":["_root"],"selector":"a[itemprop='telephone']","multiple":false,"delay":0},{"id":"telnummer","type":"SelectorText","parentSelectors":["link_naar_telnummer"],"selector":"a[itemprop='telephone']","multiple":false,"regex":"","delay":0}]}

This is the data:

This is one of the previews:

But, (now comes the problem) the export to CSV is empty!
Only the headers (first line) is visible.

What am I doing wrong? Can some help me?

Regards, Peter