IMAP Configuration In Exchange Server 2016 for External Client

Hi friends I need to configure IMAP in Exchange server 2016.Already OWA/Autodiscover/ECP are working.But some of external users we need to configure IMAP.Below steps already done,
->Service started of IMAP4 and IMAP4BE
->Configuration for the External client done through Set Imap setting command
->Cerficate Assigned to IMAP services through ECP->Servers->Certificate option
->IMAP over SSL:993 and IMAP over TLS:143 configured

But when i try to configure outlook through IMAP for external client getting error a secure connection cannot be established
amitpatelenggSystem AdminAsked:
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timgreen7077Connect With a Mentor Exchange EngineerCommented:
I have always used SAN for all things exchange. the name space that you are attempting to connect to also needs to be on the cert. so if you are connecting to imap.domain.com that name needs to be on the cert. name space can be whatever you chose.
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viktor grantConnect With a Mentor Exchange ServersCommented:
Hi,

Have you checked that the port 143 and 993 are open in your firewall?

Can you establish communication with this port externally?

Try to telnet and to check.

Cheers
Viktor
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timgreen7077Exchange EngineerCommented:
Also the firewall needs to forward those ports to the proper exchange servers.
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amitpatelenggSystem AdminAuthor Commented:
Yes I have checked both port 993 and 443 open from firewall and telnet is also tested ok.
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timgreen7077Exchange EngineerCommented:
have you confirmed the ports are forwarded to the exchange servers on your firewall for inbound IMAP traffic. internal test is fine but what about external.
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viktor grantExchange ServersCommented:
HI,

Yes eaxctly you need to be sure from external.

Internally it is working?

Cheers
Viktor
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amitpatelenggSystem AdminAuthor Commented:
From External i am able to telnet on both port 143 and 993.Also check the Rules in Firewall for inbound traffic is ok.For IMAP external config which certificate needs to apply SAN or Wildcard.I have two Exchange servers in DAG.
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amitpatelenggSystem AdminAuthor Commented:
Thanks for the Reply. I have also assigned SAN for the IMAP services for External client.But in our environment Citrix Load balancer configured with Exchange server 2016.Is there any role of Citrix load balancer for IMAP connectivity from external?
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timgreen7077Exchange EngineerCommented:
I don't know much about load balancers but the load balancers will need to know where to send the IMAP traffic if the load balancers manage your inboud exchange traffic weather it's smtp, pop, OWA, or IMAPA.
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timgreen7077Exchange EngineerCommented:
its also possible you wull have to add the cert to the load balancers for SSL. Not 100% sure though.
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viktor grantExchange ServersCommented:
No more replies from the author...it seems timgreen7077 resolved the issue
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