we can not add friends
I have the same problem. Friends of mine play OSM. I can't add them, they can't add me. Is it because I'm connected with Facebook and they aren't?
It could be that you're playing on the world version while your friends play on the dutch version. You all must play on the same version in order to add yourselves and play together.
"It's fine to celebrate success but it is more important to heed the lessons of failure." -- Bill Gates