Odd problem with Outlook 2016 connected to Exchange 2010 SP3. When Outlook is in Cached mode, after Outlook is launched I get a "Windows Security" dialog box saying connecting to (email address) I can only press cancel as nothing happens
otherwise.
Then down the bottom right in Outlook it'll say "Need Password"
I never actually get prompted for the password and simply clicking on Need Password will change the status to disconnected, then within 30 seconds it changes to Connected and Outlook starts syncing no problem. This happens every time Outlook is
launched in cached mode. Setting Outlook to not used cached mode works perfectly - no boxes, no issues. There are no issues with OWA or activesync / devices.
The only 2 things I know Outlook does in cached mode is Public Folder hierarchy check and OAB sync. There WAS a problem with the Public Folder Database, and in the end it was removed and a new one created, and set as default against the Mailbox
DB store. Outlook can now view PF folder structure now no problems. I have checked OAB syncing and permissions and it looks fine; downloading a full address book through Outlook goes through no issues. Connectivity analyzer finds no problems either with autodiscover
etc. Have tried turning off Public Folder OAB distribution too.
Tried turning off download shared mailboxes Outlook setting hasn't helped.
Tried on different Machines with Outlook 2016 as well as different mailboxes on the same server. Tried wiping out stored credentials with credential manger, deleting OST, re-creating Profiles and hasn't help so it has to be something on the Exchange
server or some odd Outlook 2016 bug since there is no issues with Outlook 2010 or 2013.
I discovered doing an IISreset then starting Outlook works perfectly only the FIRST time, subsequent launches of Outlook 2016 fail to connect as it should (but will always connect after pressing cancel, then "need password" and waiting
about 30 seconds).
I then narrowed it down further to the IIS MSExchangeServicesAppPool if I stop/start it then launch Outlook it connects fine the first time. If I do a recycle then Outlook will also connect fine the first time. So I have set it to auto recycle ever
60 minutes as a work around for now but has anyone got any suggestions as soon more users will have Outlook 2016 and will present more of an issue!