Hello @ten9eighty 

To be able to share mobile data you also have to add all 3 mobile numbers to your ‘voordelen’, you can do that here: https://www.kpn.com/combivoordeel/aanmelden.htm

After that it should be possible to share data with your family members.

You can find here more information about sharing data (in Dutch):

That was the first thing I tried. I try to add them and it tells me…

“Het is nog niet gelukt om je aan te melden, mogelijk ben je al aangemeld.
Een mislukte aanmelding kan komen door één van onderstaande redenen.”

I know I’m putting the info in correctly. I’m copying it directly from my KPN account where all the numbers and address are listed 
 

Sometimes it doesn't work, a KPN employee can add the numbers manually for you.

You can call customer service on 0800-0402 so they can do it.

Or a KPN moderator on the forum can also do it for you, if you want that fill out your forum profile and also add all 3 numbers to it.

Thanks for the info. I filled out my profile completely to include customer number and all three phone numbers. Hopefully a moderator picks this up soon.  

Hi @ten9eighty,welcome on our forum! I see you already connected the subscriptions. it seems our system got stuck on your request, I've reset the request and everything should be working now!