Thanks Mark, 

I don't have iptables or other firewall block this port, it is behind a load balancer and port 993 is open. I am pretty sure it's something in my configuration which I linked above:
https://pastebin.com/M3XG9DXA


On Mon, Jun 22, 2020 at 7:36 PM Mark Stevens <manager@monmouth.com> wrote:

make sure ports are set correctly in IPtables as it seems to be failing on TLS/SSL (open port 993)

Mark

On 6/22/2020 12:19 PM, Dshah wrote:
Dear all,

I am stuck on this issue for days, I am able to connect on my IMAP server using Apple mail client but thunderbird shows me this error: "improper command pipelining after EHLO"

I have tried all the ports in manual config but it just is not working while Apple Mail is able to connect perfectly,

here are my configuration details of "postconf -n" , "doveconf -n" and "master.cf"

Thanks in advance.