trying to add a custom Email address to the "From" drop down in the Se

trying to add a custom Email address to the "From" drop down in the Send Email smart service.
Followed the exact steps in the Appian documentation to do this but getting the attached error in the drop down instead of the proper display name. Any idea why?

ERROR: ???address.johnDoe.displayName???...

OriginalPostID-136822

OriginalPostID-136822