1 files changed, 1 insertions, 1 deletions
diff --git a/lib/net/smtp.rb b/lib/net/smtp.rb
index ab9c1afb88..29b7c0b71c 100644
--- a/lib/net/smtp.rb
+++ b/lib/net/smtp.rb
@@ -794,7 +794,7 @@ module Net
 
     def rcptto_list(to_addrs)
       raise ArgumentError, 'mail destination not given' if to_addrs.empty?
-      to_addrs.each do |addr|
+      to_addrs.flatten.each do |addr|
         rcptto addr
       end
     end