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On prem Exchange here
Exchange 2016 CU14 + Outlook 2016 Users - Everything was ok
Exchange 2016 CU18 + Outlook 2016 Users with Cached mode on - Outlook prompt for password and crash with chart.dll error file
Exchange 2016 CU18 + O365 - Everything is ok
I have done the following :
Removing Cached mode resolve the issue, but i would like to keep that on.
Anything else i should check ?
Nick
Forgot to say i also get chart.dll error
Ok, did check the Negociate item in the MAPI virtual directory. A good and a bad news.
1st the good one : It seems to have fix the password prompt for my Outlook 2016 users, but only when internal to the company.
2nd the bad one : Now all my users are getting a password prompt, but only when not connected to the enterprise infrastructure. If i'm inside the network or via VPN everything seems normal.
I remember searching this in the pass and end up unchecking the Negotiate in MAPI, but maybe that was not the trick to solve all the problems. Weird enough is that everything was running smoothly On CU14 but not when updating in CU18, so maybe something broken in the update or i forgot to check somewhere in web.config files.
Here my plan :
Any thought is really appreciated.
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Hi @Nicholas Terreault ,
I remember searching this in the pass and end up unchecking the Negotiate in MAPI
I've also seen similar issues resolved by removing Negotiate for MAPI. This might because Outlook is not able to switch from "Negotiate" to "NTLM" when connecting from outside the corporate network. That being said, as checking Negotiate didn't perfectly fix the current problem, personally I am assuming that it's worth trying to remove the Negotiate for MAPI, and meantime, go to the Autodiscover and EWS directories in IIS and remove "Negotiate" from the list of providers for Windows Authentication, then restart IIS and see if there would be any improvement.
Here are two links for your reference:
MAPI over HTTP - Outlook prompting for credentials
MAPI over HTTP – Outlook Password Prompt on Domain joined External Users
Hi @Nicholas Terreault ,
Exchange 2016 CU18 + Outlook 2016 Users with Cached mode on - Outlook prompt for password and crash with chart.dll error file
Does this occur to all Exchange 2016 CU18 + Outlook 2016 Users in your environment?
When does the password prompt appear, at launch or when you are using Outlook?
As regards to the chart.dll error, would you please remove any personal information involved such as email address or domain name etc and then share a screenshot of the error so that we can do further research on this?
Besides, I did some research about Outlook 2016 and chart.dll error, according to the discussion under several relevant links, it seems that the error could be related to some third-party antivirus software. So if the affected users happen to have this kind of software installed, it's suggested to try temporarily disabling it and see if there would be any improvement.
Reference: Outlook 2016 and chart.dll error (multiple PCs)
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It happen to all my 2016 users with cached mode on.
For testing, i removed our antivirus and no more chart.dll error once antivirus is gone and cached mode turn on. So there is an interraction somewhere between the Antivirus and Outlook.
As for password prompt, i get it at the start of outlook and is happening with or without antivirus installed. This has started right after installation of CU18, maybe that broke something in the authentication method, but where do i look ?
I really appreciate the help,
Thanks,
Also getting event 63 / Outlook on the pc
Service web Exchange GetAppManifest error code 0 and answer code HTTP:401
Additional error message : an unknow error happen with error code est80004005
Thanks
Hi @Nicholas Terreault ,
As per your concern about the authentication method, please open IIS, expand Default Web Site and Exchange Back End, select the virtual directory on the left hand pane, choose Authentication on the right hand pane, then compare the authentication method for each virtual directories(both frontend and backend) with the default settings in the link below:
Default settings for Exchange virtual directories
With that confirmed, please open EAC, go to servers > virtual directories, check the authentication method configured on Exchange. Below are the settings for autodiscover, EWS and mapi in my lab, you can compare with the settingson your end:
Please open up cmd as administrator and type “IISRESET” if you make any change.
Regarding the Event 63, I did some research and find the following link which mentioned a similar error message, from the discussion there, issue was finally resolved by recycling the MSExchangeServicesAppPool in IIS. So I'd like to suggest giving it a go at your convenience and see if it works.
https://community.spiceworks.com/topic/2229293-exchange-2010-to-2016-migration-some-users-can-t-see-mailtips
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@Nicholas Terreault ,
I'd like to follow up to see how things are going with this issue? Feel free to post back if you need further assistance on this.
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Did some tests. 1st i would like to say i'm missing the check for Windows authentication - Negotiate on MAPI Virtual Discovery. I will change that, as soon as i can.
Also what puzzle me is, if i recycle the MSExchangeServicesAppPool Outlook 2016 connect fine for just... 1 time once i close and reopen password prompt is coming back. Is it related to the Negotiate not check MAPI Virtual Discovery ? I just don't want to recycle every couple of minute.
I will let you know for the Negotiate part, should be next week-end or a night this week.
Thanks @Nicholas Terreault for getting back! Regarding the Negotiate part, feel free to have a go at your convenience and see if it works.
As per recycling the MSExchangeServicesAppPool can temporarily fix the password prompt issue ONCE, it's indeed a little bit weird. I did some research, but currently cannot find relevant documentation stating if this is related to the authentication method on MAPI virtual directory. So maybe we can wait for the Negotiate test in a few days and see how it goes. Meanwhile, before the issue gets resolved, if the password prompt issue is severely impacting the users, I'd like to suggest configuring the pool to recycle on a schedule like 10 minutes as a temporary workaround.