I am newbie to sharepoint.
I've created a Library in office 365 name as Course Material. I've enable the version and required checkout from Library setting.
Now when I select the document and click on check-out, version updated successfully and work file open in work online perfectly. Now when I try to edit the document it shows me error
Image : http://prntscr.com/9bbwoj I don't know what is wrong
Can you close the document from all browsers, and enter the site with an admin account, and make sure that no one is checking out the document, then check it out and try to edit.
You should be able to click on the ellipses menu (...), and choose "Advanced" then choose "Check Out", after that you can click on the document and once you type something, it will ask you if you want to edit it, you don't really need to hit save as it will save the changes automatically.
