diff --git a/src/ruby/lib/grpc/generic/rpc_server.rb b/src/ruby/lib/grpc/generic/rpc_server.rb
index 0e318bd53b8fb5e693a40af13cc8d35f1783ed79..410156ff03398698e995fdbb8cb49f833d45cd44 100644
--- a/src/ruby/lib/grpc/generic/rpc_server.rb
+++ b/src/ruby/lib/grpc/generic/rpc_server.rb
@@ -48,6 +48,8 @@ module GRPC
         return false
       when 'TERM'
         return false
+      when nil
+        return true
       end
     end
     true