ls -la /etc/ssl/certs ?
did you also run update-ca-certificates -f ?
# ls /etc/ssl/certs/ISRG_Root_X1.pem
/etc/ssl/certs/ISRG_Root_X1.pem
update-ca-certificates -f
and
dpkg-reconfigure ca-certificates
did both, result is same 
# openssl verify /etc/letsencrypt/live/mydomain.com/cert.pem
C = US, O = Internet Security Research Group, CN = ISRG Root X1
error 2 at 2 depth lookup: unable to get issuer certificate
error /etc/letsencrypt/live/mydomain.com/cert.pem: verification failed
To solve the problem, you need in order:
- Make sure that the CA ISRG Root X1 is installed on your system (in /etc/ssl/certs) : PEM AVAILABLE HERE
- Remove the old X3 (mozilla) CA which has expired
Alas
The problem is not related to letsencrypt plugin.
It is - verify certs with openssl, which return error: "certificate has expired" or "unable to get issuer certificate" (if disable expired DST certificate).
Trick: "$rs = 0;" after "... execute" (/var/www/imscp/engine/PerlLib/iMSCP/OpenSSL.pm:138)
The solution is stupid, but working...
I use it on my debian 10 servers
Still required?
There is a patched version of imscp-1.5.3-201830800 for installation to debian 10 (buster) + MariaDB 10.5
While i-MSCP setup, did you also enabled IPv6 for bind9?
Yes
IMSCP 1.3.16
When password recovered by user, it doesn't change for access to /stats (Basic Auth)
Hi
IMSCP 1.3.16
/etc/apache2/sites-available/01_awstats.conf
ls -l /usr/share/awstats/icon/mime/document.png
lrwxrwxrwx 1 root root 16 дек 28 2013 /usr/share/awstats/icon/mime/document.png -> notavailable.png
(xsl|swf|document|csv|... - symbol links)
Result: 403 to symlink icons ...
<Directory /usr/share/awstats/icon/>
Options FollowSymLinks
??
