diff --git a/app/models/client.rb b/app/models/client.rb
index 9a9007300..070308d3b 100644
--- a/app/models/client.rb
+++ b/app/models/client.rb
@@ -273,7 +273,7 @@ def check_language
 
   def check_certificate
     Array.wrap(certificate).each do |c|
-      errors.add(:certificate, "Certificate #{c} is not included in the list of supported certificates.") unless ["CoreTrustSeal", "DIN 31644", "DINI", "DSA", "RatSWD", "WDS").include?(c)
+      errors.add(:certificate, "Certificate #{c} is not included in the list of supported certificates.") unless ["CoreTrustSeal", "DIN 31644", "DINI", "DSA", "RatSWD", "WDS"].include?(c)
     end
   end