May 15 2019
I'm currently facing a problem for which I cannot find a solution. (Ok it's obvious because I won't be there if I had a solution ;) )
We have an Hybrid installation of O365
The problem is between
- User in O365
- Secondary mailbox On-Premise
Context: In Outlook 2016
- I have my own mailbox as primary (on O365)
- I have two secondary mailboxes On-Premise (Exchange 2016)
- I have two secondary mailboxes (O365)
- Connected to the internal network of the company, each mailboxes are accessible without any issues
- Connected outside my organization, only my own mailbox and secondary mailbox on O365 are available
- The 2 secondary mailboxes On-premise are not accessible and I have the standard error message "Cannot expand the folder. The set of folder cannot be opened. etc."
So I guess there is a problem on our firewall who is blocking something between O365 and On-Premise but I did not see anything on the monitoring of this firewall
Does anyone have an idea of what could be the problem on my issue ?
Thanks in advance