aaPanel_Kern Yep, it was associate to the rightful IP, which is my server IP, regardless I just re-install the mail server to give it a fresh restart. However the Postfix-install and Sqlite-support takes too much time to repair for operation. Is it normal? Tried several times but still not Ready its status. Same issue with this questions
aaP_johncharlie1272
What is your operating system? what version?
The A record used by the mail server cannot be an open proxy, and the resolved IP must be the IP of the server
aaPanel_Kern Here our operating system System: Debian GNU/Linux 11 x86_64(Py3.7.9) we dont have concern at A record yet, were having trouble in installing and uninstalling the mail server itself. Its very frustrating now. Can you help by checking it?
aaP_johncharlie1272
Hello, it is recommended to use ubuntu 20 or debian 10. Has debian 11 been adapted yet?
aaPanel_Kern But were always using Debian 10, for context, we already used the mail server for the last 2 years without having issues. Just now from last month we encountered issues, Id sent an email please check. TIA
aaP_johncharlie1272
Debian GNU/Linux 11
Not adapted yet
it is recommended to use ubuntu 20 or debian 10
aaPanel_Kern Yeah agree, it's weird I just checked, our OS provider upgraded us to Debian 11, but were from Debian 10, that why we have a mail server before. Any alternative for mail server compact with Debian 11?
As I said before: debian11 without adaptation cannot be used normally
aaPanel_Kern 
Seems we have a little progress here, dovecot working, openssl, sqlite and other are all in a green status (worked) what are your thoughts about this last error?
aaP_johncharlie1272
Use this website to check if the A record, mx record used by the domain name mail server points to the IP of the server
https://dnschecker.org/all-dns-records-of-domain.php
aaPanel_Kern Okay okay I get it. I used DNS resolver to re-point our server IP to the A record. Now how can I clean up the mail server, as mentioned that I reinstall the mail server, but why our emails, still there? If I uninstall the mail server it should be wipe right? Yet, all the emails are still there and I want it to be clean. How to clear it? Also since Im starting from start again adding a new domain, and it always says "The domain name already exist" so im assuming the first domain was still save and never clean up after I uninstall the mail server?
aaP_johncharlie1272
Move or change the name of the /www/vmail directory
aaPanel_Kern This solved everything. SUCCESSFULLY INSTALLED and SETUP MAIL SERVER for DEBIAN 11
