grid layout – dipe one half

The form layout is the one below, but the fields are on two rows instead of one.
On my staging site it worked well, and I just migrated it using the tools provided by Siteground.

[dipe_row]
[dipe_one_half]
<label>[text* your-firstname placeholder “Voornaam”]</label>
[/dipe_one_half]
[dipe_one_half]
<label>[text* your-name placeholder “Naam”]</label>
[/dipe_one_half]
[/dipe_row]
[dipe_row]
[dipe_one_half]
<label>[email* email-adres placeholder “E-mail”]</label>
[/dipe_one_half]
[dipe_one_half]
<label>[tel telephone placeholder “Telefoon”]</label>
[/dipe_one_half]
[/dipe_row]`

The page I need help with: [log in to see the link]