I try to open a word/excel/office document from a SharePoint 2013 server.
Until last week that worked fine, when opening a pptx file in Office Web Applications and then clicked on "Open in PowerPoint", the document opened in MS PowerPoint 2007 (local on my computer) and above the slides, I saw a new menu bar "server presentation" with a large button "check out". I then could check the document in and thus create a new version on the SharePoint server.
Now (since some days) I don't see this "server presentation" menu bar anymore, the office document is saved locally on my computer and not connected to the SharePoint server and its original storage location anymore, so I can not check it out or check it in easily.
This is only the case on my computer, in others, it still works.
Any ideas/suggestions what is the problem?
EDIT
The problem only seems to occur, when I log in to the network via VPN. When I connected directly to the company network via Ethernet, everything is ok.