How to fix YouTube's Your settings could not be saved: Invalid request, authentication expired.
31WARNING - I will NOT be held responsible for any damages the software(s) and methods shown in this video may cause to yours or someone else's computer, hardware, software, and/or data, including loss of use of such devices and/or loss of data and/or loss of account use and/or loss of profits from the resulting inability to use such accounts, devices and data. Any information or program you choose to put into use from this video is done AT YOUR OWN RISK. As a precaution, I recommend backing up any irrecoverable data before installing and using ANY new software(s), including those shown in this video.
This video will show you a quick and easy fix in order to get past the following error message Mozilla FireFox users may be experiencing when making any submission or modification to the information (text) on the video's page (including submission, approval and modification of comments): Your settings could not be saved: Invalid request, authentication expired.
The error message in a red bar with an exclamation mark ( ! ) may also appear as the following when trying to submit, approve, or otherwise modify comments in a video's page: Error, Try again.
Many sources claim that the error message is related to one's YouTube (or Google's Gmail account) not being verified, and that verifying your account through account verification should solve the problem. The problem is: for those of us who already have verified accounts, re-verifying your account does not in any way change this behaviour and associated error messages.
UPDATE: New evidence would lead to believe that this issue was being caused by new YouTube page scripting not being compatible with the Video DownloadHelper Add-On for Mozilla FireFox (which I have installed in my Mozilla FireFox browsers). As this tutorial may help others should the problem arise once again, I will leave it up on my YouTube page. Should this problem resurface, in theory, disabling the Video DownloadHelper Add-On in Mozilla FireFox SHOULD theoretically correct the problem until Video DownloadHelper's programmers patch Video DownloadHelper to correct the problem (as they did May 28, 2013).