When we choose in the action information "Include Request Email" for the request email type, the email notification fails. Otherwise the email is delivered.
The root cause of the notification failing is because of a missing image file from the Service catalog installed directory.
You will notice the following error in the logs:
C:\Program Files\CA\Service Catalog\filestore\themes\
1) Please make sure that the header_logo.png file is present at C:\Program Files\CA\Service Catalog\filestore\themes\common\images\logo folder.
2) In case you are replacing the logo with a custom logo, change the name to header_logo.png.
3) Check if the image file is corrupted, replaces if found from another working environment.