Email cannot be delivered: No such user in mail authorization database

Applicable to:

Email does not get delivered to john.doe@example.com, the following errors appear in /var/log/maillog:

CONFIG_TEXT: dovecot_authdb_plesk[1377]: No such user 'john.doe@example.com' in mail authorization database
dovecot: auth: plesk(john.doe@example.com): Mail account information for user='john.doe@example.com' was not found
dovecot: auth: Debug: userdb out: NOTFOUND#0111
dovecot: service=lda, user=john.doe@example.com, ip=[]. Debug: auth input:
postfix/pipe[14513]: E141A88AA5: to=<john.doe@example.com, relay=plesk_virtual, delay=2, delays=2/0/0/0.06, dsn=4.2.1, status=deferred (Message can not be delivered at this time )
The same errors may appear after switching from Courier to Dovecot if messages are forwarded internally.
The list of affected accounts might be received as below:

# MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysql -uadmin psa -Ne "select concat(m.mail_name,'@',d.name) as mailbox, a.type, a.password from domains d, mail m, accounts a where m.dom_id=d.id and m.account_id=a.id and m.postbox='true' and a.password =''"

The mail account (recipient) has an empty password in Plesk database.

For a single email account

Log into Plesk.
Set password at Domains > example.com > Email Addresses > john.doe@example.com:

For numerous mail accounts

Connect to the server via SSH
List all accounts affected by the issue and save them in a text file:

# MYSQL_PWD=`cat /etc/psa/.psa.shadow` mysql -uadmin psa -Ne "select concat(m.mail_name,'@',d.name) as mailbox from domains d, mail m, accounts a where m.dom_id=d.id and m.account_id=a.id and m.postbox='true' and a.password =''" > /root/select.txt
Make a mass password set:

# while read i; do /usr/local/psa/bin/mail -u $i -passwd 'PASSWORD'; done < /root/select.txt