diff --git a/lib/network.rb b/lib/network.rb
index 7ac5f3e..f230456 100644
--- a/lib/network.rb
+++ b/lib/network.rb
@@ -50,6 +50,8 @@ def get_build
     def update_build(id, state, trace)
       broadcast "Submitting build #{id} to coordinator..."
 
+      trace = trace.encode('UTF-8', 'binary', invalid: :replace, undef: :replace, replace: '')
+
       options = default_options.merge(
         state: state,
         trace: trace,