For international group mail  recipients are not able to recievw mail but it shows in recipient list.

somegroup@groups.int.example.com

Creating jobs in Jenkins using .yml file

for ex:

• email-ext:
  recipients: priyanga.g@example.com siva-subramaniam.m@example.com thavamani.raja@example.com nithya.ganesan@example.com somegroup@groups.int.example.com smegroup@example.com gavin.brebner@example.com 
  content-type: html

Note: 

somegroup@example.com==> can able to see the mail

somegroup@groups.int.example.com==>not able to see