I haven't been able to insert images in any of my posts today (30-Jan-2017). When I click the IMCE (insert image) button on the toolbar of the editor, the opened window shows "waiting for community.norton.com..." in the bottom left of the status bar, and the following error is always displayed after about a minute or so: "Error 503 first byte timeout".
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32-bit Vista Home Premium SP2 * Firefox v51.0.1 * NIS v22.8.1.14