Sent an attachment with emailer transformer does not work

Without seeing the error message, I assume that the error is that the Emailer can't find/access the file to be attached? Maybe for testing try sending it within your domain if you think authentication could be the issue.

Couple of recommendations - if you are writing a shapefile to be emailed, you should zip it up.

Then, the FeatureWriter outputs a _dataset attribute which is the filepath to what it wrote. It's very convenient to use that in your Emailer, instead of having to type in the filepath.

If you have an FME Server, instead of the Emailer it is easier to use the FMEServerEmailGenerator -> FMEServerNotifier transformers to send email.

I changed the workbench with your recommendations. Making a zip file from the shape was the solution. It works sending within the domain but outside the domain it does not work. I will ask that to our IT guys. 😀 Thanks you for your help!