The operating system my web server runs on is (include version):
My hosting provider, if applicable, is:
Sorry, this may be simple, I'm a bit of a newbie.
So I used certbot --apache to install certificates on my domain along with the two subdomains.
When I use ssllabs for mail.armanpopat.co.uk I'm told that
'Issuer Let's Encrypt Authority X3'
but when I use open ssh and use the command:
' s_client -starttls smtp -crlf -connect mail.armanpopat.co.uk:587'
I'm told that 'issuer=/CN=mail.armanpopat.co.uk'
and 'Verify return code: 18 (self signed certificate)'
This is causing me problems when I try to use thunderbird to send emails.
Any help would be appreciated.