diff --git a/app/models/doi.rb b/app/models/doi.rb
index b5b650ad8..3c1d77b7e 100644
--- a/app/models/doi.rb
+++ b/app/models/doi.rb
@@ -1779,7 +1779,7 @@ def check_dates
   def check_rights_list
     Array.wrap(rights_list).each do |r|
       errors.add(:rights_list, "Rights '#{r}' should be an object instead of a string.") unless r.is_a?(Hash)
-      errors.add(:rights_list, "Rights should not have a length of more than 2000 characters.") if r["rights"].length > 2000
+      errors.add(:rights_list, "Rights should not have a length of more than 2000 characters.") if r["rights"].to_s.length > 2000
     end
   end