Solved Migrated posts cannot be edited

after updating to the latest version 6.0.4, you still cannot edit pre-migration posts.

Do you have experience with the database? With phpMyAdmin you can insert this sql command. Instead of #__ you have to enter your prefix.
UPDATE `#__kunena_messages` SET `email` = NULL;
This should solve the problem, but create a database backup first.

You will not be confused by the title of the topic that I put on from an unsolved thread that has been closed.

After upgrading to 6.0.4, as I edited posts from pre-migration, the message "Cannot save message: Invalid email address!" problem no longer exists and changes (edit post) are not taken into account. After pressing save just nothing happens (returns to its original state without any message).

It's ok in new posts. This is for pre-migration posts.

Have you already recounted the statistics and synchronized the users (in the Backend -> Kunena ->Tools)?
If that does not help, open the browser console (press F12) and edit a post. Maybe an error message will be displayed.

After calculating the statistics and synchronizing the users (done positively),
after editing a post from before migration, now two known messages are displayed:

1) The message has been successfully edited - (this is not true because no changes have been made).
2) Cannot save message: Invalid email address!

Briefly describing it is as it was before the update to 6.0.4.

Maybe this table was not adjusted properly during the upgrade. Try what I suggested in my first answer.