transactional emails won't be sent

[melaxon]

When order is placed no message will ne sent.
When I comment an order in backend I receive this popup:
Zend\Mail\Transport\Smtp transport expects either a Sender or at least one From address in the Message; none provided

No records on Email Logs

"Contact us" works normally

magento 2.3.0
Swissup_Email just updated. previous version did the same

[0m3r]

0. Did you try to disable Swissup_Email?
1. What is your full number version of Magento?

cd [magento_root]
php bin/magento --version
git tag

I have seen a similar problem before with Magento 2.3.0 in core magento/magento2#16938. There was a bug with the 'from' header.

It was fixed at Magento core.
magento/magento2@7b9e807

[melaxon]

finally it's not swiss_email fault. When it is disabled the problem persists but no error message appears.

It was solved when I upgraded Magento to the latest version 2.3.1
By the way the latest 2.2.x is also okay
So it only happened in 2.3.0