Could not send message using @title to user ID 1

message is still wrong as the user is not the user it's being sent to

In message_subscribe, the code clones the message, sets the clone's owner to the recipient, and sends the clone. See Drupal\message_subscribe\Subscribers::sendMessage(). There may be other use cases where it doesn't work this way.

In any case, this is a separate issue from whether the title is appearing properly.

Hi! I had the same message in my app. In my case, I send emails to a queue.

I analyzed the classes MessageNotifierBase and Email code for the send(), deliver() and postSend() methods. I reached the place that returns boolean - this is the deliver() method. It seems to me that a value should be passed in the $result['result'] parameter, where it returns TRUE, FALSE or NULL. And there is an isset() check that returns TRUE or FALSE.

In my case $result['result'] returns NULL because the message is queued (not sent immediately). So in postSend() is passed NULL and it does not enter the condition ($result === FALSE).

This should solve the problem of sending emails when using a queue, e.g. queue_mail module.

Hi! I've updated patch *-9 according to #3364862 Wrong return value of deliver function in notifier plugin Email.php 🐛 Wrong return value of deliver function in notifier plugin Email.php Fixed change.

This patch should go into an issue fork and merge request.

Patch works good for me :) Thx for your work

I just created a MR with the changes from message_notify-could_not_send_message-2936095-10.patch

It seems we have to adjust the tests as well