[ms office - 2016] Moved email to O365, now getting errors in Outlook 2016

[timbo343]

The move from exchange 2010 to O365 has gone fairly well and pain free with the exception of what im now seeing in Outlook 2016.]

 

There's 2 issues..

 

1. when configuring a new connection / profile on outlook and the wizard goes through it's start up, when it comes to checking the email address i get a certificate error stating the name on the security certificate is invalid.

 

It would seem this certificate is pointing to mail.externaldomain.co.uk. I have an entry in both external DNS and internal DNS CNAME pointing mail.externaldomain.co.uk to outlook.office365.com. Also have the same setup for autodiscover but this is pointing to autodiscover.office365.com.

 

2. If i accept the above issue, things seem to work with one little niggle, outlook keeps wanting to authenticate with O365.

 

I should just add that we are using a smoothwall for our filtering and firewall.

 

When we had a connection to the OnPrem Exchange server, we didn't have any of these issues.

 

I've also removed the mail.externaldomain.co.uk certificate from our certificate store too.

 

[Steve21]

Sorry cant find the IP as I'm out the country but there's a list of IPs you need to bypass https inspection on so smoothie doesn't replace the cert and cause that issue

 

If you view the cert I'm assuming it's a smoothie one that's being reissued currently?

 

Steve

[snagrat]

This is the current list https://support.office.com/en-gb/article/Office-365-URLs-and-IP-address-ranges-8548a211-3fe7-47cb-abb1-355ea5aa88a2

[timbo343]

Thank you, thats stopped the certificate issue, would it stop outlook asking for credentials too?

[Steve21]

If you haven't clicked the remember password item it'll re-ask a few times once the password store has expired

 

The only way to get truly seamless is to use something like modern authentication etc (Generslly we find those who stay on a computer click remember and those who move often generally used owa as they can't be bothered to setup every pc, but modern auth is in my list to do!)

 

Steve

Edited August 1, 2017 by Steve21

[timbo343]

If you haven't clicked the remember password item it'll re-ask a few times once the password store has expired

 

The only way to get truly seamless is to use something like modern authentication etc (Generslly we find those who stay on a computer click remember and those who move often generally used owa as they can't be bothered to setup every pc, but modern auth is in my list to do!)

 

Steve

 

thanks, will have to have a look at Modern Authentication. We only have about 15 staff that use Outlook, the rest will all use OWA.