Reinstall internetsecurity 2015

Last year I bought AVG Internet security complete with 3 licensees, expire date 05-03-2017
Version 2015.0.6201
I successfully install it on a desktop and 2 laptops. 
Last week I de install it from a laptop because in had to reinstall Windows. 

Now I want to reinstall AVG protection.
I just downloaded internet security and have to fill in my license number. But when I paste it, or type it…(I check it several times) de install button remains gray… so it doesn’t work.

First time in about 8 years I have this problem with AVG. It never has been difficult for me to activate any AVG product. Anybody knows what the problem is? Is something changed in the procedure, do I maybe use ZEN now to do this? 

Hello Bart,
We really appreciate your efforts which you have taken to fix it. Upon checking with your account we can see that you have no active products which registered under your account. Since you have mentioned that you have  purchased AVG Internet security for 3 license, unfortunately we couldn't find that. No need to worry, we have sent you the email instruction to locate your account. Please try to share the information so that we can assist you further. Thank you.