Mail-Exchange Issue

[LarryJoe33]

Here is a tough one to explain but I'll give it a shot and hope there is someone who had this problem and may be an expert on firewalls and exchange. Our IT department at work (which reports to me ironically) can't resolve it.

Two days ago in the middle of the day, Mail had an error message next to it. I clicked it and it asked me for my exchange password. I have been getting my work email through Mail for 6 months with no issues. I enter my password and I get "failed to verify username or password". Nothing changed on my Mac or the exchange server environment (that I am aware of). IT tells me the server is authenticating the ask of Mail but my Mac disconnects immediately. Here are things I know:

- same issue with using Outlook 2016
- same issue trying to get mail for a different exchange account through my machine. It's not just my account.
- Outlook web mail works fine
- I booted to an old build of High Sierra when it worked fine and have the same issue
- Does this whether on the company ethernet or home on my wifi
- Phones, iPads, Win10 machine all getting email just fine

That's about all I can tell you. Just a shot in the dark that this may ring a bell based on the limited information I can provide. My first thought when it started was that the firewall was blocking my MBP.

Thanks in advance.

 

[techwarrior]

Reboot, seriously.

This occasionally happens to me with Exchange\Outlook 2016 in Mac.

Apparently, there is a difference in the algorithms Apple and MS use for security. From what I recall, the TLS connection uses an algorithm to increment the key over time. Apple has a different timer as to how long this can go on before re-establishing the connection.

The only way I have found to reset it is to reboot. To prevent (or reduce instances of) it, I always shut down Outlook and\or Mail when I leave for the day. So, the lack of a constant connection seems to force a new secure session when I launch the app the next day. The calendar and other sync services down seem to be impacted, perhaps they re-establish a session regularly rather than maintain a session?

I read one article, related to O365 to remove some entries in Keychain related to Exchange and MS, apparently the keychain entries created a while back(maybe with Office 2011 or early Office 2016 releases) are different than those being used by MS currently, and allowing the Apps to re-establish keychain entries might be a fix. Unknown if it is relevant if not using O365, but couldn't hurt to try.

• Exchange
• Microsoft Office Identities…
• MSOpenTech.*
• Some “OC” keychain entry that might be unrelated

Presumably, do this with Outlook closed, and you will be prompted to login next time you launch it. Same would hold for Lync\Skype4B, etc. If using O365, probably make sure all of the MS apps are not running when you do this.

 

[LarryJoe33]

Reboot, seriously.

This occasionally happens to me with Exchange\Outlook 2016 in Mac.

Apparently, there is a difference in the algorithms Apple and MS use for security. From what I recall, the TLS connection uses an algorithm to increment the key over time. Apple has a different timer as to how long this can go on before re-establishing the connection.

The only way I have found to reset it is to reboot. To prevent (or reduce instances of) it, I always shut down Outlook and\or Mail when I leave for the day. So, the lack of a constant connection seems to force a new secure session when I launch the app the next day. The calendar and other sync services down seem to be impacted, perhaps they re-establish a session regularly rather than maintain a session?

I read one article, related to O365 to remove some entries in Keychain related to Exchange and MS, apparently the keychain entries created a while back(maybe with Office 2011 or early Office 2016 releases) are different than those being used by MS currently, and allowing the Apps to re-establish keychain entries might be a fix. Unknown if it is relevant if not using O365, but couldn't hurt to try.

• Exchange
• Microsoft Office Identities…
• MSOpenTech.*
• Some “OC” keychain entry that might be unrelated

Presumably, do this with Outlook closed, and you will be prompted to login next time you launch it. Same would hold for Lync\Skype4B, etc. If using O365, probably make sure all of the MS apps are not running when you do this.

Thanks, I really appreciate the comprehensive response. I will pass this long to my IT team. I have restarted the MBP many times. I am guessing the server and meraki FW need to be restarted as well.

 

[techwarrior]

Just client side reboots, shouldn't need server side reboots.

Try the keychain cleanup.

 

[LarryJoe33]

We upgraded something called EIO Board on our server on Wednesday when this started. Team is working on it now. EIO goes through our Outlook web address to communicate with Exchange. So does my Mac. Stay tuned.