User.Email in data binding returns array in "Send email" action node -> can't send email


I’m trying to send an email to a single recipient using the email stored in User.Email.

To make sure that only one user is selected I’m using a filtered table with cardinality one.

However, I consistently get “SendEmailException: Expected params.Source to be a string” and when I check the Debug info I see that the recipient is returned as an array. Example:
“to”: [

When I return the content of that same data binding using “Log to Console”, I get a string containing the email address.

And yes, I could extract User.Email and save it to another object class but that defeats having a relational data model. :wink:

Maybe the User object class has special properties? Maybe its connected to deleting and creating users with the same email and the user not being completely deleted?

Many thanks in advance.


Could you please take some screenshots of the Send Email action node, Datasource you are using in the databinding and the devTools?

Thanks :slightly_smiling_face:

// Erik

Send email action:

Datasource used in email action:

Filter used for datasource:

Datasource used in filter:

“Relation” between Kunde-Bruker and Service as in the data model:

Content of the datasource used in the send email action as shown in the dev tools:

And the Debug info:


Seems like the error is not the data source for the recipient. When a single-cardinality data source is used to map the email and name of the recipient, the log is just like you have posted. With without the “providerError”:


  1. Can you test the same action, but with a hardcoded email address instead, to see if it is related to the recipient datasource, the email content, or mailgun/aws?
  2. It may also be related to the sender address. Are you using a custom mailgun or AWS account for sending? And is Send email working in general other places with that same sender address?

You may DM details about the provider. Also, it would be nice with info on which solution and environment this error occurs (and a timestamp for the last error, for us to see if our logs reveals anything, or if this error is thrown by a third party).


  1. Doesn’t work with hardcoded email address either.

  2. Seems to be AWS. I’ll check with whoever set it up.

  3. Other emails do get sent.