Hello Lord,

You can use also the id number for search your friends , or pass your id to them ....

I've just tested from the app , section friends and works fine for me .

I advice you to perform the troubleshooting steps 

https://social-support.plarium.com/hc/en-us/categories/7602939511964-Loading-Technical

or,

if still persist you can submit a ticket to the support here :

https://social-support.plarium.com/hc/en-us/requests/new?fbclid=IwAR3BQvJCine1yBvcEA36YRyEptBiql9BrsUsBZlB-J0g0Sy6cZeuI4RIYgM

But i repet , at the moment i don't see any issues with add friends and also others can send me a friend request.

I think there's a limit on how many friends the game will let you have, could be you've reached that.  Maybe try removing an old one you no longer talk to and see if that lets you add somebody new.  

ok but the problem is that I can't delete the old one 

Have you tried from plarium play app?

How can i remove friends from Stormfall age of war?

i

 In your plarium play app, you click on friends, than on the profile of the firend u want to be removed than on the 3 dots and last step is unfriend.