Webform/SwiftMailer - TypeError in encodeString() - must be of the type string, array given
The cause and my solution:
In the Webform's email handler configuration -&gt; &quot;Send from (website/domain)&quot; section -&gt; &quot;From email&quot; field, I used the [site:mail] token.
In EsmtpTransport.php line 378, the $address parameter had a value of [&quot;email@example.com&quot; =&gt; string(0)].
By modifying the &quot;From email&quot; field to &quot;Site email address&quot; solved my problem.
Hope this helps.