If so, they claim the SSL certificate is pre-installed. The “WordPress Hosting” subscription has an “DV SSL-certificate” included, perhaps a Let’s Encrypt certificate.
If you actually do have such a subscription (probably, as you said you don’t a root login and you are using WordPress), chances are you’re better of with asking Vevida support for help with this problem.
No, @Osiris, I am not using the wordpress-hosting from Vevida. I have the site installed myself. I am using the cheaper hosting option (and Wordpress hosting wasn’t available when I started).
Hmm. It's probably not possible for you to install a Let's Encrypt certificate yourself. Vevida sells a DV certificate with the "Extra Veilig - Een extra veilige website voor jou én je klanten, met zichtbare SSL en 7 dagen back-up." option for € 3/month.
I'm guessing you're using the "WP Encrypt" plugin for WordPress, correct? And tried to get a certificate through the following screen:
If you don't have permissions to modify the server configuration, you might be able to still use the certificates if your host provides an interface to upload your own SSL certificates. In that case you can simply upload the generated certificate files there.
And that first part about "permissions to modify the server configuration" is a problem: with shared webhosting, you don't have those permissions. So, you're left with the rest of that text: hoping your service provider (Vevida) allows you to upload certificates into some kind of interface, like cPanel. Vevida probably doesn't offer that, as they sell SSL certificates to their clients themselves. But you can always ask Vevida support!
"(…) with visible SSL (…)" is the most accurate translation IMO, probably pointing to a green padlock, i.e. "valid in browsers" or something like that.