

So, in order to conduct further researches on your issue, please try to rename your outlook datafile(.ost) and then restart your Outlook to see if the issue could be resloved. And usually corrupted datafile may cause issues like this.

As I know, differences between Exchange cache mode and Exchange "Online mode" are OST and OAB. Since you have mentioned that everything can work fine in Outlook for web and Exchange "Online mode", it seems that your issue is more related to your Outlook desktop client. Please make sure you have upgraded your Outlook to the latest version.ĭo all of other users in your working environment have the same issue? What's the version of your Outlook? (File > Office Account > About Outlook).
