Mail client problem

Hi,
I upgraded succesfully from debian 9 with ispconfig 3.2.8p2 to debian 10. The upgrade went well but it is no more possible access to the mail using an external client (thunderbird,outlook....). If I use webmail the mail works perfectly. Where should I verify the missing configuration?
Thank you!
Christian

 

Yes, I run a ispconfig update --force (because I've already had the newest version) with a reconfigure service yes. Probably I made a mistake ansering YES at "Create new ISPConfig SSL certificate". The default was NO but I choose YES

 

dovecot: imap-login: Error: Failed to initialize SSL server context: Can't load DH parameters: error:1408518A:SSL routines:ssl3_ctx_ctrl:dh key too small
dovecot: imap-login: Disconnected: TLS initialization failed. (no auth attempts in 1 secs): user=<>

 

It works, perfectly, but obviously the certificate is not trusted because it is auto generated.
Could I follow this tutorial to use let's encrypt to have a signed certificate?
https://www.howtoforge.com/tutorial/securing-ispconfig-3-with-a-free-lets-encrypt-ssl-certificate/

 

No, It is written in the first row
How could I do?

 

My server has been upgraded from 3.1 and probably the auto creation and configuration of a let's encrypt certificate didn't work correctly for some reason.
Could I follow that guide anyway to verify where could be the problem?

 

I run the ispconfig_update --force answering yes to create a new SSL certificate.
My hostname -f point to the IP of the server but the certificate created is not emitted by let's encrypt and is not a trusted certificate.

 

I read the document, but I notice something strange.
There is no logs in the file: /var/log/letsencrypt at the time I run ispconfig_update.sh --force

 

I checked and I do not have the /root/.acme.sh/ directory on my system

 

ls -la /root/.acme.sh/
ls: impossibile accedere a '/root/.acme.sh/': File o directory non esistente (File or directory not exists)


ls -la /etc/letsencrypt/
totale 84
drwxr-xr-x 9 root root 4096 ott 27 03:00 .
drwxr-xr-x 130 root root 12288 ott 31 23:19 ..
drwx------ 3 root root 4096 mag 3 2020 accounts
drwx------ 19 root root 4096 ott 22 00:14 archive
drwxr-xr-x 2 root root 20480 ott 26 03:04 csr
drwx------ 2 root root 20480 ott 26 03:04 keys
drwx------ 19 root root 4096 ott 22 00:14 live
-rw-r--r-- 1 root root 952 lug 19 2020 options-ssl-apache.conf
drwxr-xr-x 2 root root 4096 ott 26 03:04 renewal
drwxr-xr-x 5 root root 4096 mag 2 2020 renewal-hooks
-rw-r--r-- 1 root root 64 lug 19 2020 .updated-options-ssl-apache-conf-digest.txt

 

Ok, but I still don't understand why my ispconfig installation does not have a valid certificate to use https and server connections on ftp and mail.
I have already forced the ispconfig installation and nothing is written in the letsencrypt log during the install process as I wrote few posts ago.
Is it correct?