diff --git a/src/AuthorizedSocketConnection.js b/src/AuthorizedSocketConnection.js
index b3d9fbfd..7a9fca3c 100644
--- a/src/AuthorizedSocketConnection.js
+++ b/src/AuthorizedSocketConnection.js
@@ -190,8 +190,12 @@ export default class AuthorizedSocketConnection<TContext, TCredentials> {
       try {
         resultOrStream = await sourcePromise;
       } catch (err) {
-        this.subscriptions.delete(id);
-        throw err;
+        if (err instanceof GraphQLError) {
+          resultOrStream = { errors: [err] };
+        } else {
+          this.subscriptions.delete(id);
+          throw err;
+        }
       }
 
       if (resultOrStream.errors != null) {