Also, when I send the test email in the tab -> configuation -> sendinblue, then on mobile the sender name is like this:
from: _sendername?=
In the newsletter I sent the other day people received it on mobile devices as:
From: =?utf-8?q?sendername=E2=84=...
I turned off the SMTP (obsolete) function and added the api key in the sendinblue addon section.
after sending the testmail I got this notification:
Unable to check the webhook, please verify the API key: cURL error 28: Resolving timed out after 5000 milliseconds