I have a strange situation after upgrading to exchange 2013 some users are reporting that they cannot open or create calender appointments for calenders they used to be able to manage. we currently are using outlook 2010. also when the users access the calenders with the webmail they are reporting that they can access the calenders and are able to do all the things they need to do.
i have tried reinstalling office and adding their exchange accounts but this does not help.
another stange thing is that to be sure i had setup the correct access policy i have reset all the security entries on all the calendars with the help of powershell. this seemed to have helped but after a couple of hours some users started reporting that they could not access calendar items again!