Partner Community users in Salesforce may encounter the following error when they attempt to send an email using a Lightning email template from the email composer: "We couldn't send your email. Please try again."
Cause:
Starting with the Spring '19 release, Salesforce introduces a separate sharing process for Lightning email templates, along with enhanced folders. Because this sharing mechanism is different from Classic templates, Partner Community users cannot access or use Lightning email templates. Classic email templates continue to work as expected for Partner Community users.
This is expected behavior for Partner Community users. The recommended resolution is to use a Classic email template instead of a Lightning email template.
If you are not using a template and still receive this error, verify the following permissions are enabled on the user's profile:
The Salesforce Product team is evaluating community use cases and requirements for a future release. If you would like to see Lightning email template support for Partner Community users in a future release, consider posting your request on the Salesforce Idea Exchange.
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