This has just started to occur this week. We have been using Windows 7 with the Volume License version of Office 2013 for about a year.
When launching an Office application such as Word or Excel, the end user is prompted to logon to the proxy to access messaging.office.com.
What feature is attempting to use messaging.office.com and how do you turn it off.
Please note that we do have Group Policy in place that has been recommended by others...
User Configuration- Administrative Templates- Microsoft Office 2013- Tools | Options | General | Service Options...- Online Content
Online Content Options = Enabled
Online content options = Do not allow Office to connect to the Internet
This policy has been in place since Office was 1st implemented and has worked well until recently. I did confirm that no changes had been made to Group Policy and that the policy is being applied propelry to the clients.
We do have some stand alone "click-to-install" versions of Office 2013 but I have not had reports of this behavior on any of those systems yet.
I thought that maybe this issue was caused by a recent Office Update but the issue seemed to show up before I approved the latest bunch of Office updates on our WSUS server. I could be mistaken... I did notice a One Drive update, we don't use this feature, I am thinking of trying to remove that update but like I said, according to end-user reports, the issue started a couple days prior to this update.
After trying to make a proxy exclusion for a quick work-around, one user (so far) reported a dialogue for "Connecting to messaging.office.com" as opposed to the original message - "Connecting to proxy Server for messaging.office.com". As if it is trying to logon to the messaging.office.com domain itself. I verified this message on her system.
I also had a report of the proxy message attempting to connect to office15Client.microsoft.com.
Again, we have been using Office 2013 for over a year with the current Group Policy & configuration and never had received any proxy log on prompts. Any help would be appreciated.