Can not drop an Article from Peer to Peer Transactional Replication

Hello.

I'm working with SQL Server 2014 and configure P2p Transactional Replication between two instances; So each of them is active for Insert,Update and Delete action.

Now i want to drop an Article from publication, but I can't. 

From Management Studio i get this error:

TITLE: Microsoft SQL Server Management Studio
------------------------------
Object reference not set to an instance of an object. (CreatePubWizard)

And by T-SQL:

EXEC sp_droparticle   
  @publication = N'pub1',   
  @article = N't1',  
  @force_invalidate_snapshot = 1; 

I get this error:

Msg 14046, Level 16, State 1, Procedure sp_MSrepl_droparticle, Line 286 [Batch Start Line 1]
Could not drop article. A subscription exists on it.

I don't want to drop subscription. I have tried it in each instances and i have got same error on both of them. 

What can i do?

Thanks.