smtp send email on unattended upgrades in Ubuntu

Hello I have setup unattended upgrades on my Ubuntu 20.04 server with msmtp and sendmail. And want to send the result of Unattended-Upgrade to my email. But the email is not sending by Unattended-Upgrade!

I have add my email Adress to the Unattended-Upgrade settings:

Unattended-Upgrade::Mail "me@yahoo.de";

My /etc/mail.rc looks like:

set sendmail="/usr/bin/msmtp -t"

My msmtp config (/etc/msmtprc) looks like:

defaults
port 587
tls on
tls_starttls on
tls_trust_file /etc/ssl/certs/ca-certificates.crt

account me@yahoo.de
host smtp.mail.yahoo.com
from me@yahoo.de
auth on
logfile /var/log/msmtp
user me@yahoo.de
password abc
account default: me@yahoo.de
aliases /etc/aliases

With the permissions:

ls -l /etc/msmtprc    
-rw-r----- 1 root msmtp 2741 Dec 15 12:23 /etc/msmtprc

The same config I have in my user Dir (/home/me/.msmtprc):

ls -l /home/me/.msmtprc                                       
-rw------- 1 me msmtp 2725 Dec 15 09:51 /home/me/.msmtprc

Now I'm able to successfully send emails with:

echo "content" | mail -s "test email" me@yahoo.de

the log of the command above in /var/log/msmtp is:

Dec 15 13:04:31 host=smtp.mail.yahoo.com tls=on auth=on user=me@yahoo.de from=me@yahoo.de recipients=me@yahoo.de mailsize=153 smtpstatus=250 smtpmsg='250 OK , completed' exitcode=EX_OK

But when I run unattended-upgrade manually sudo /usr/bin/unattended-upgrade -d I get:

bla bla bla
bla bla bla
bla bla bla
Sending mail to me@yahoo.de
sendmail: the server sent an empty reply
sendmail: could not send mail (account default from /etc/msmtprc)
mail returned: 76

The log of the cammand above is:

Dec 15 13:23:03 host=smtp.mail.yahoo.com tls=on auth=on user=me@yahoo.de from=me@yahoo.de recipients=me@yahoo.de errormsg='the server sent an empty reply' exitcode=EX_PROTOCOL