Unknown mysql password format: 'unknown'

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DirectAdmin Task Queue Log shows several lines DATE+TIME + Unknown mysql password format: 'unknown'
The Date/Time corresponds to the backup time (Admin backup/transfer).

I checked:
#cat /usr/local/directadmin/scripts/setup.txt
And used the root password "#mysql -uroot -p" and was able to login in MariaDB 5.5.41

#cat /usr/local/directadmin/conf/mysql.conf
And used the da_admin password "#mysql -uda_admin -p" and was able to login in MariaDB 5.5.41.

I have no idea how long this is going on, it seems I have not checked this log for a while.

When the backup has finished, I see no errors in the ticket. It just shows 'user xx has been backed up.
2020:02:20-03:10:03: Unknown mysql password format: 'unknown' (shown: 4 times)
2020:02:20-03:10:04: Unknown mysql password format: 'unknown' (shown: 3 times)
2020:02:20-03:11:26: Unknown mysql password format: 'unknown'

And the ticket output:
User admin has been backed up. <3:10:03>
User u001 has been backed up. <3:10:06>
User u002 has been backed up. <3:10:06>
User u003 has been backed up. <3:11:25>
User u004 has been backed up. <3:11:39>

I left out the remaining users that were backed up, the date and time of the errors cover the shown backups.

I extracted the backup for u001, it has several databases.
The backup contained folder "backup/" and in there I saw several files named xxx_cccc.sql
Those files contained real backup data, so the error in the Task Queue did not disrupt the backup. AFAIK.

(Googling this error gave 1 hit, in this forum, 2011, and the question was not answered as people got sidetracked I guess).

 

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Found it, with help of Direct Admin Support.

The easiest way to solve this is to check in mysql which users have no password.
(SELECT * FROM mysql.users)
If you see users with a password field not filed up with hexadecimal digits, but showing the word 'unknown' then write down the username.
Now login as admin in your control panel, click on 'change password for a user) in the left column, type in the username, and now give it the original password it already has to login. It will update the mysql password for you.
If you do not know the password for this user, you can assign a new one. Don't forget to tell the user about this.

In my case, the user does not use his mysql login, I told him to always create a new db user per domain, to keep everything nice and separated.
So there was no problem, all databases were backed up all the time, the error does not have any implications, but I like error logs to be empty, so that when a real error occurs, it will jump right at you.

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